Electrical techniques for biomarker detection in a cochlea

ABSTRACT

A method, including energizing one or more electrodes of a cochlear electrode array to induce a current flow in the cochlea at a plurality of temporal locations, measuring one or more electrical properties at one or more locations in the cochlea resulting from the induced current flow at the plurality of different temporal locations and determining whether or not trauma has occurred based on a change between the measured electrical properties from the first temporal location to the second temporal location.

BACKGROUND

This application is a Continuation application of U.S. Pat. ApplicationNo. 17/042,607, filed Sep. 28, 2020, which is a National Stage ofPCT/IB2019/052414, filed Mar. 25, 2019, which claims priority to U.S.Provisional Application No. 62/647,896, entitled ELECTRICAL TECHNIQUESFOR BIOMARKER DETECTION IN A COCHLEA, filed on Mar. 26, 2018, namingJohn Michael Heasman of East Melbourne, Australia as an inventor, theentire contents of that application being incorporated herein byreference in its entirety.

BACKGROUND

Hearing loss, which may be due to many different causes, is generally oftwo types: conductive and sensorineural. Sensorineural hearing loss isdue to the absence or destruction of the hair cells in the cochlea thattransduce sound signals into nerve impulses. Various hearing prosthesesare commercially available to provide individuals suffering fromsensorineural hearing loss with the ability to perceive sound. A hearingprosthesis can be a cochlear implant.

Conductive hearing loss occurs when the normal mechanical pathways thatprovide sound to hair cells in the cochlea are impeded, for example, bydamage to the ossicular chain or the ear canal. Individuals sufferingfrom conductive hearing loss may retain some form of residual hearingbecause the hair cells in the cochlea may remain undamaged.

Individuals suffering from hearing loss typically receive an acoustichearing aid. Conventional hearing aids rely on principles of airconduction to transmit acoustic signals to the cochlea. In particular, ahearing aid typically uses an arrangement positioned in the recipient’sear canal or on the outer ear to amplify a sound received by the outerear of the recipient. This amplified sound reaches the cochlea causingmotion of the perilymph and stimulation of the auditory nerve. Cases ofconductive hearing loss typically are treated by means of boneconduction hearing aids. In contrast to conventional hearing aids, thesedevices use a mechanical actuator that is coupled to the skull bone toapply the amplified sound.

In contrast to hearing aids, which rely primarily on the principles ofair conduction, certain types of hearing prostheses commonly referred toas cochlear implants convert a received sound into electricalstimulation. The electrical stimulation is applied to the cochlea, whichresults in the perception of the received sound.

Many devices, such as medical devices that interface with a recipient,have structural and/or functional features where there is utilitarianvalue in adjusting such features for an individual recipient. Theprocess by which a device that interfaces with or otherwise is used bythe recipient is tailored or customized or otherwise adjusted for thespecific needs or specific wants or specific characteristics of therecipient is commonly referred to as fitting.

SUMMARY

In accordance with an exemplary embodiment, there is a method,comprising energizing one or more electrodes of a cochlear electrodearray to induce a current flow in the cochlea at a plurality of temporallocations, measuring one or more electrical properties at one or morelocations in the cochlea resulting from the induced current flow at theplurality of different temporal locations, and determining whether ornot trauma has occurred based on a change between the measuredelectrical properties from the first temporal location to the secondtemporal location.

In accordance with an exemplary embodiment, there is a method,comprising causing current to flow from a first electrode of anintra-cochlea electrode array to a second electrode of the intra-cochleaelectrode array at a plurality of temporal locations, measuring, at athird electrode and a fourth electrode of the intra-cochlea electrodearray, respective voltages induced by the flowing current at theplurality of temporal locations, determining that a change between thevoltage measurements at the third electrode and the fourth electrode hasoccurred between the temporal locations, determining a time periodbetween the temporal locations, and determining whether or not aphenomenon has occurred within the cochlea based on the determined timeperiod.

In accordance with an exemplary embodiment, there is a method,comprising applying at first and second temporal locations respectiveelectrical currents to one or more electrodes located in a cochlea of arecipient, obtaining first and second data indicative of an electricalproperty at a location within the cochlea, the first and second datacorresponding to data obtained, respectively, at the first and secondtemporal locations, evaluating whether or not there is an existence of atemporal change in an electrical property within the cochlea at thelocation based on the obtained data, and determining whether or notthere is blood and/or a clot in the cochlea based on the temporal changein the electrical property.

In accordance with an exemplary embodiment, there is a method,comprising applying at a plurality of temporal locations respectiveelectrical currents to respective one or more electrodes located in acochlea of a cochlear electrode array, and obtaining a plurality ofrespective measurement readings from electrodes within the cochlealocated along the electrode array for the respective electricalcurrents, wherein the method includes moving the electrode array in thecochlea, and the action of obtaining the plurality of respectivemeasurement readings is executed such that the readings are focused at asame location within the cochlea relative to other locations within thecochlea.

In accordance with an exemplary embodiment, there is a method,comprising inserting a cochlear implant electrode array into a cochlea;and interleaving neural response measurements with impedancemeasurements between electrodes of the cochlear implant electrode arrayduring the insertion.

In accordance with an exemplary embodiment, there is a method,comprising applying an electrical current to one or more electrodes ofan electrode array located in a cochlea of a recipient, obtaining dataindicative of impedances between a plurality of groups of two electrodescorresponding respectively to different locations along the electrodearray, evaluating electrical conductivity between the respectiveelectrodes of the respective groups, determining the existence of animpedance change between the respective electrodes of the respectivegroups, and determining a location, density, and temporal feature of theimpedance change.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are described below with reference to the attached drawings,in which:

FIG. 1A is a perspective view of an exemplary hearing prosthesis inwhich at least some of the teachings detailed herein are applicable;

FIG. 1B depicts a side view of the cochlear implant 100 outside of therecipient;

FIGS. 2A and 2B are side views of an embodiment of an insertion guidefor implanting a cochlear implant electrode assembly such as theelectrode assembly illustrated in FIG. 1 ;

FIGS. 3A and 3B are side and perspective views of an electrode assemblyextended out of an embodiment of an insertion sheath of the insertionguide illustrated in FIG. 2 ;

FIGS. 4A-4E are simplified side views depicting the position andorientation of a cochlear implant electrode assembly insertion guidetube relative to the cochlea at each of a series of successive momentsduring an exemplary implantation of the electrode assembly into thecochlea;

FIGS. 5-9 are exemplary system components of an exemplary embodiment;

FIG. 10 depicts an exemplary 4 point impedance measurement;

FIGS. 11-13 present exemplary data according to some embodiments;

FIGS. 14-19 present exemplary algorithms for exemplary methods;

FIGS. 20-28 present exemplary data according to some embodiments;

FIGS. 29 and 30 present exemplary algorithms for exemplary methods;

FIG. 31 presents an exemplary schematic useful for explaining anembodiment;

FIG. 32 presents exemplary data according to some embodiments; and

FIG. 33 presents an exemplary algorithm for an exemplary method.

DETAILED DESCRIPTION

FIG. 1A is a perspective view of a cochlear implant, referred to ascochlear implant 100, implanted in a recipient, to which someembodiments detailed herein and/or variations thereof are applicable.The cochlear implant 100 is part of a system 10 that can includeexternal components in some embodiments, as will be detailed below.Additionally, it is noted that the teachings detailed herein are alsoapplicable to other types of hearing prostheses, such as by way ofexample only and not by way of limitation, bone conduction devices(percutaneous, active transcutaneous and/or passive transcutaneous),direct acoustic cochlear stimulators, middle ear implants, andconventional hearing aids, etc. Indeed, it is noted that the teachingsdetailed herein are also applicable to so-called multi-mode devices. Inan exemplary embodiment, these multi-mode devices apply both electricalstimulation and acoustic stimulation to the recipient. In an exemplaryembodiment, these multi-mode devices evoke a hearing percept viaelectrical hearing and bone conduction hearing. Accordingly, anydisclosure herein with regard to one of these types of hearingprostheses corresponds to a disclosure of another of these types ofhearing prostheses or any medical device for that matter, unlessotherwise specified, or unless the disclosure thereof is incompatiblewith a given device based on the current state of technology. Thus, theteachings detailed herein are applicable, in at least some embodiments,to partially implantable and/or totally implantable medical devices thatprovide a wide range of therapeutic benefits to recipients, patients, orother users, including hearing implants having an implanted microphone,auditory brain stimulators, pacemakers, visual prostheses (e.g., bioniceyes), sensors, drug delivery systems, defibrillators, functionalelectrical stimulation devices, etc.

In view of the above, it is to be understood that at least someembodiments detailed herein and/or variations thereof are directedtowards a body-worn sensory supplement medical device (e.g., the hearingprosthesis of FIG. 1A, which supplements the hearing sense, even ininstances when there are no natural hearing capabilities, for example,due to degeneration of previous natural hearing capability or to thelack of any natural hearing capability, for example, from birth). It isnoted that at least some exemplary embodiments of some sensorysupplement medical devices are directed towards devices such asconventional hearing aids, which supplement the hearing sense ininstances where some natural hearing capabilities have been retained,and visual prostheses (both those that are applicable to recipientshaving some natural vision capabilities and to recipients having nonatural vision capabilities). Accordingly, the teachings detailed hereinare applicable to any type of sensory supplement medical device to whichthe teachings detailed herein are enabled for use therein in autilitarian manner. In this regard, the phrase sensory supplementmedical device refers to any device that functions to provide sensationto a recipient irrespective of whether the applicable natural sense isonly partially impaired or completely impaired, or indeed never existed.

The recipient has an outer ear 101, a middle ear 105, and an inner ear107. Components of outer ear 101, middle ear 105, and inner ear 107 aredescribed below, followed by a description of cochlear implant 100.

In a fully functional ear, outer ear 101 comprises an auricle 110 and anear canal 102. An acoustic pressure or sound wave 103 is collected byauricle 110 and channeled into and through ear canal 102. Disposedacross the distal end of ear channel 102 is a tympanic membrane 104which vibrates in response to sound wave 103. This vibration is coupledto oval window or fenestra ovalis 112 through three bones of middle ear105, collectively referred to as the ossicles 106 and comprising themalleus 108, the incus 109, and the stapes 111. Bones 108, 109, and 111of middle ear 105 serve to filter and amplify sound wave 103, causingoval window 112 to articulate, or vibrate in response to vibration oftympanic membrane 104. This vibration sets up waves of fluid motion ofthe perilymph within cochlea 140. Such fluid motion, in turn, activatestiny hair cells (not shown) inside of cochlea 140. Activation of thehair cells causes appropriate nerve impulses to be generated andtransferred through the spiral ganglion cells (not shown) and auditorynerve 114 to the brain (also not shown) where they are perceived assound.

As shown, cochlear implant 100 comprises one or more components whichare temporarily or permanently implanted in the recipient. Cochlearimplant 100 is shown in FIG. 1 with an external device 142, that is partof system 10 (along with cochlear implant 100), which, as describedbelow, is configured to provide power to the cochlear implant, where theimplanted cochlear implant includes a battery that is rechargeable viathe transcutaneous link.

In the illustrative arrangement of FIG. 1A, external device 142 cancomprise a power source (not shown) disposed in a Behind-The-Ear (BTE)unit 126. External device 142 also includes components of atranscutaneous energy transfer link, referred to as an external energytransfer assembly. The transcutaneous energy transfer link is used totransfer power and/or data to cochlear implant 100. Various types ofenergy transfer, such as infrared (IR), electromagnetic, capacitive andinductive transfer, may be used to transfer the power and/or data fromexternal device 142 to cochlear implant 100. In the illustrativeembodiments of FIG. 1 , the external energy transfer assembly comprisesan external coil 130 that forms part of an inductive radio frequency(RF) communication link. External coil 130 is typically a wire antennacoil comprised of multiple turns of electrically insulated single-strandor multi-strand platinum or gold wire. External device 142 also includesa magnet (not shown) positioned within the turns of wire of externalcoil 130. It should be appreciated that the external device shown inFIG. 1 is merely illustrative, and other external devices may be usedwith embodiments of the present invention.

Cochlear implant 100 comprises an internal energy transfer assembly 132which can be positioned in a recess of the temporal bone adjacentauricle 110 of the recipient. As detailed below, internal energytransfer assembly 132 is a component of the transcutaneous energytransfer link and receives power and/or data from external device 142.In the illustrative embodiment, the energy transfer link comprises aninductive RF link, and internal energy transfer assembly 132 comprises aprimary internal coil 136. Internal coil 136 is typically a wire antennacoil comprised of multiple turns of electrically insulated single-strandor multi-strand platinum or gold wire.

Cochlear implant 100 further comprises a main implantable component 120and an elongate electrode assembly 118. In some embodiments, internalenergy transfer assembly 132 and main implantable component 120 arehermetically sealed within a biocompatible housing. In some embodiments,main implantable component 120 includes an implantable microphoneassembly (not shown) and a sound processing unit (not shown) to convertthe sound signals received by the implantable microphone in internalenergy transfer assembly 132 to data signals. That said, in somealternative embodiments, the implantable microphone assembly can belocated in a separate implantable component (e.g., that has its ownhousing assembly, etc.) that is in signal communication with the mainimplantable component 120 (e.g., via leads or the like between theseparate implantable component and the main implantable component 120).In at least some embodiments, the teachings detailed herein and/orvariations thereof can be utilized with any type of implantablemicrophone arrangement.

Main implantable component 120 further includes a stimulator unit (alsonot shown) which generates electrical stimulation signals based on thedata signals. The electrical stimulation signals are delivered to therecipient via elongate electrode assembly 118.

Elongate electrode assembly 118 has a proximal end connected to mainimplantable component 120, and a distal end implanted in cochlea 140.Electrode assembly 118 extends from main implantable component 120 tocochlea 140 through mastoid bone 119. In some embodiments, electrodeassembly 118 may be implanted at least in basal region 116, andsometimes further. For example, electrode assembly 118 may extendtowards apical end of cochlea 140, referred to as cochlea apex 134. Incertain circumstances, electrode assembly 118 may be inserted intocochlea 140 via a cochleostomy 122. In other circumstances, acochleostomy may be formed through round window 121, oval window 112,the promontory 123 or through an apical turn 147 of cochlea 140.

Electrode assembly 118 comprises a longitudinally aligned and distallyextending array 146 of electrodes 148, disposed along a length thereof.As noted, a stimulator unit generates stimulation signals which areapplied by electrodes 148 to cochlea 140, thereby stimulating auditorynerve 114.

FIG. 1B is a side view of a cochlear implant 100 without the othercomponents of system 10 (e.g., the external components). Cochlearimplant 100 comprises a receiver/stimulator 180 and an electrodeassembly or lead 118. Electrode assembly 118 includes a helix region182, a transition region 184, a proximal region 186, and anintra-cochlear region 188. Proximal region 186 and intra-cochlear region188 form an electrode array assembly 190. In an exemplary embodiment,proximal region 186 is located in the middle-ear cavity of the recipientafter implantation of the intra-cochlear region 188 into the cochlea.Thus, proximal region 186 corresponds to a middle-ear cavity sub-sectionof the electrode array assembly 190. Electrode array assembly 190, andin particular, intra-cochlear region 188 of electrode array assembly190, supports a plurality of electrode contacts 148. These electrodecontacts 148 are each connected to a respective conductive pathway, suchas wires, PCB traces, etc. (not shown) which are connected through lead118 to receiver/stimulator 180, through which respective stimulatingelectrical signals for each electrode contact 148 travel.

Electrode array 146 may be inserted into cochlea 140 with the use of aninsertion guide. It is noted that while the embodiments detailed hereinare described in terms of utilizing an insertion guide or other type oftool to guide the array into the cochlea, in some alternate insertionembodiments, a tool is not utilized. Instead, the surgeon utilizes hisor her fingertips or the like to insert the electrode array into thecochlea. That said, in some embodiments, alternate types of tools can beutilized other than and/or in addition to insertion guides. By way ofexample only and not by way of limitation, surgical tweezers like can beutilized. Any device, system, and/or method of inserting the electrodearray into the cochlea can be utilized according to at least someexemplary embodiments.

The teachings detailed herein are directed towards identifyingphenomenon inside a cochlea. Some embodiments can include utilizingimaging (e.g., CT scan, X-ray, etc.), which require the patient to beexposed to radiation during the process of obtaining medical images, aswell as the need for medical equipment in the operating room to provideand otherwise obtain the imaging, as well as a subsequent analysis by anexpert to assess the correct insertion of the electrode holder. Someembodiments of the teachings detailed herein utilize such, while otherembodiments specifically do not utilize such, but instead utilize othermethods to evaluate or otherwise obtain information indicative of agiven electrode array insertion scenario. Some embodiments include theaction of measuring neuronal activation after stimulation. Thisexemplary embodiment can require subjective expert analysis and/or canalso be dependent on having a good / acceptable neural response.However, in some instances, such is not always obtainable. Again, aswith the aforementioned imaging, some embodiments herein utilize suchwhile other embodiments specifically do not utilize such methods. In atleast some exemplary embodiments, methods of determining an insertionscenario can utilize voltage measurements in the cochlea. In anexemplary embodiment of such embodiments, the interpretation of theobtained voltage measurements still requires subjective analysis by anexpert. In addition, these measurements can be rendered more difficultto interpret than otherwise might be the case by the presence ofso-called air bubbles, open electrodes, shorted electrodes, and/orelectrode extrusion. Some embodiments of the teachings detailed hereinutilize the aforementioned voltage measurements coupled with expertanalysis, while in other embodiments some of the teachings detailedherein specifically avoid utilization of expert analysis to obtain orotherwise analyze and electrode array insertion scenario.

Some embodiments include obtaining voltage measurements from insideand/or outside the cochlea and analyzing them in, by way of example onlyand not by way of limitation, an automated manner, by comparing thevoltage measurements to statistical data.

FIG. 2A presents a side view of an embodiment of an insertion guide forimplanting an elongate electrode assembly generally represented byelectrode assembly 145 (corresponding to assembly 190 of FIG. 1B) into amammalian cochlea, represented by cochlea 140. The illustrativeinsertion guide, referred to herein as insertion guide 200, includes anelongate insertion guide tube 210 configured to be inserted into cochlea140 and having a distal end 212 from which an electrode assembly isdeployed. Insertion guide tube 210 has a radially-extending stop 204that may be utilized to determine or otherwise control the depth towhich insertion guide tube 210 is inserted into cochlea 140.

Insertion guide tube 210 is mounted on a distal region of an elongatestaging section 208 on which the electrode assembly is positioned priorto implantation. A robotic arm adapter 202 is mounted to a proximal endof staging section 208 to facilitate attachment of the guide to a robot,which adapter includes through holes 203 through which bolts can bepassed so as to bolt the guide 200 to a robotic arm, as will be detailedbelow. During use, electrode assembly 145 is advanced from stagingsection 208 to insertion guide tube 210 via ramp 206. After insertionguide tube 210 is inserted to the appropriate depth in cochlea 140,electrode assembly 145 is advanced through the guide tube to exit distalend 212 as described further below.

FIG. 2B depicts an alternate embodiment of the insertion guide 200, thatincludes a handle 202 that is ergonomically designed to be held by asurgeon. This in lieu of the robotic arm adapter 202.

FIGS. 3A and 3B are side and perspective views, respectively, ofrepresentative electrode assembly 145. As noted, electrode assembly 145comprises an electrode array 146 of electrode contacts 148. Electrodeassembly 145 is configured to place electrode contacts 148 in closeproximity to the ganglion cells in the modiolus. Such an electrodeassembly, commonly referred to as a perimodiolar electrode assembly, ismanufactured in a curved configuration as depicted in FIGS. 3A and 3B.When free of the restraint of a stylet or insertion guide tube,electrode assembly 145 takes on a curved configuration due to it beingmanufactured with a bias to curve, so that it is able to conform to thecurved interior of cochlea 140. As shown in FIG. 3B, when not in cochlea140, electrode assembly 145 generally resides in a plane 350 as itreturns to its curved configuration. That said, it is noted thatembodiments of the insertion guides detailed herein and/or variationsthereof can be applicable to a so-called straight electrode array, whichelectrode array does not curl after being free of a stylet or insertionguide tube, etc., but instead remains straight.

FIGS. 4A-4E are a series of side-views showing consecutive exemplaryevents that occur in an exemplary implantation of electrode assembly 145into cochlea 140. Initially, electrode assembly 145 and insertion guidetube 310 are assembled. For example, electrode assembly 145 is inserted(slidingly or otherwise) into a lumen of insertion guide tube 300. Thecombined arrangement is then inserted to a predetermined depth intocochlea 140, as illustrated in FIG. 4A. Typically, such an introductionto cochlea 140 is achieved via cochleostomy 122 (FIG. 1 ) or throughround window 121 or oval window 112. In the exemplary implantation shownin FIG. 4A, the combined arrangement of electrode assembly 145 andinsertion guide tube 300 is inserted to approximately the first turn ofcochlea 140.

As shown in FIG. 4A, the combined arrangement of insertion guide tube300 and electrode assembly 145 is substantially straight. This is due inpart to the rigidity of insertion guide tube 300 relative to the biasforce applied to the interior wall of the guide tube by pre-curvedelectrode assembly 145. This prevents insertion guide tube 300 frombending or curving in response to forces applied by electrode assembly145, thus enabling the electrode assembly to be held straight, as willbe detailed below.

As noted, electrode assembly 145 is biased to curl and will do so in theabsence of forces applied thereto to maintain the straightness. That is,electrode assembly 145 has a memory that causes it to adopt a curvedconfiguration in the absence of external forces. As a result, whenelectrode assembly 145 is retained in a straight orientation in guidetube 300, the guide tube prevents the electrode assembly from returningto its pre-curved configuration. This induces stress in electrodeassembly 145. Pre-curved electrode assembly 145 will tend to twist ininsertion guide tube 300 to reduce the induced stress. In the embodimentconfigured to be implanted in scala tympani of the cochlea, electrodeassembly 145 is pre-curved to have a radius of curvature thatapproximates the curvature of medial side of the scala tympani of thecochlea. Such embodiments of the electrode assembly are referred to as aperimodiolar electrode assembly, and this position within cochlea 140 iscommonly referred to as the perimodiolar position. In some embodiments,placing electrode contacts in the perimodiolar position provides utilitywith respect to the specificity of electrical stimulation, and canreduce the requisite current levels thereby reducing power consumption.

As shown in FIGS. 4B-4D, electrode assembly 145 may be continuallyadvanced through insertion guide tube 300 while the insertion sheath ismaintained in a substantially stationary position. This causes thedistal end of electrode assembly 145 to extend from the distal end ofinsertion guide tube 300. As it does so, the illustrative embodiment ofelectrode assembly 145 bends or curves to attain a perimodiolarposition, as shown in FIGS. 4B-4D, owing to its bias (memory) to curve.Once electrode assembly 145 is located at the desired depth in the scalatympani, insertion guide tube 300 is removed from cochlea 140 whileelectrode assembly 145 is maintained in a stationary position. This isillustrated in FIG. 4E.

Conventional insertion guide tubes typically have a lumen dimensioned toallow the entire tapered electrode assembly to travel through the guidetube. Because the guide tube is able to receive the relatively largerproximal region of the electrode assembly, there will be a gap betweenthe relatively smaller distal region of the electrode assembly and theguide tube lumen wall. Such a gap allows the distal region of theelectrode assembly to curve slightly until the assembly can no longercurve due to the lumen wall.

Returning to FIGS. 3A-3B, perimodiolar electrode assembly 145 ispre-curved in a direction that results in electrode contacts 148 beinglocated on the interior of the curved assembly, as this causes theelectrode contacts to face the modiolus when the electrode assembly isimplanted in or adjacent to cochlea 140. Insertion guide tube 300retains electrode assembly 145 in a substantially straightconfiguration, thereby preventing the assembly from taking on theconfiguration shown in FIG. 3B.

It is noted that while the embodiments above disclose the utilization ofan insertion tool, in some other embodiments, insertion of the electrodearray is not executed utilizing an insertion tool. Moreover, in someembodiments, when in insertion tool is utilized, the insertion tool isnot as intrusive as that detailed in the figures. In an exemplaryembodiment, there is no distal portion of the tool. That is, theinsertion tool stops at the location where the distal portion begins. Inan exemplary embodiment, the tool stops at stop 204. In this regard,there is little to no intrusion of the tool into the cochlea. Anydevice, system and/or method that can enable the insertion of theelectrode array can be utilized in at least some exemplary embodiments.

As can be recognized from the above, the electrode array can be utilizedto obtain the data utilized in the methods herein, such as by way ofexample only and not by way of limitation, the voltages at the readelectrodes, and can also be used to provide the stimulating electrode(just in case for some reason that was not clear). FIG. 5 depicts anexemplary system for utilizing the cochlear implant to obtain suchinformation. Presented in functional terms, there is a test unit 3960 insignal communication with unit 8310, which in turn is in signalcommunication, optionally with a unit 7720 and a unit 8320, the detailsof which will be described below.

Unit 3960 can correspond to an implantable component of an electrodearray, as seen in FIG. 1 . More specifically, FIG. 6 depicts anexemplary high-level diagram of a receiver/stimulator 8710 (theimplantable portion of 100) of a cochlear implant, looking downward. Ascan be seen, the receiver/stimulator 8710 includes a magnet 160 that issurrounded by a coil 137 that is in two-way communication (although inother embodiments, the communication is one-way) with a stimulator unit122, which in turn is in communication with the electrode array 145.Receiver/stimulator 8710 further includes a cochlear stimulator unit122, in signal communication with the coil 137. The coil 137 and thestimulator unit 122 are encased in silicon as represented by element199. In an exemplary embodiment, receiver/stimulator 8710 is utilized astest unit 3960, and is used to acquire information about electrode arrayposition.

FIG. 8 depicts an exemplary RS (receiver/stimulator) interface 7444which is presented by way of concept. An inductance coil 7410 isconfigured to establish a magnetic inductance field so as to communicatewith the corresponding coil of the receiver-stimulator of the cochlearimplant. Interface 7444 includes a magnet 7474 so as to hold theinductance coil 7410 against the coil of the receiver/stimulator of thecochlear implant in a manner analogous to how the external component ofthe cochlear implant is held against the implanted component, and howthe coils of those respective components are aligned with one another.As can be seen, an electrical lead extends from the coil 7410 to controlunit 8310, representing signal communication between interface 7444, andcontrol unit 8310. It is noted that in an alternative embodiment, 7444can be the external component of FIG. 1 , and can have some and/or allof the functionalities just described, such that data can be obtainedfrom the implanted portion outside of a clinical setting, such as duringeveryday life of the recipient.

FIG. 9 depicts an exemplary embodiment of the receiver/stimulator 8710in signal communication with the control unit 8310 via electrical leadthat extends from the interface device 7444 having coil 7410 about amagnet 7474 as can be seen. The interface device 7444 communicates viaan inductance field with the inductance coil of the receiver/stimulator8710 so that the data acquired by the implantable component 8710(receiver/stimulator) can be transferred to the control unit 8310.

Note also that in at least some alternate exemplary embodiments, controlunit 8310 can communicate with the so-called “hard ball” referenceelectrode of the implantable component of the cochlear implant so as toenable communication of data from the receiver/stimulator 8710 tocontrol unit 8310 and/or vice versa.

It is noted that in the embodiment of FIG. 9 , control unit 8310 is insignal communication with the various other components as detailedherein, which components are not depicted in FIG. 9 for purposes ofclarity.

Also functionally depicted in FIG. 5 is the optional embodiment where anelectrode array insertion robotic system / actuator system 7720 and aninput device 8320 is included in the system. In an exemplary embodiment,the input device 8320 could be a trigger of a hand held device thatcontrols the actuator system 7720 and can stop and/or start the actuatorfor insertion of the electrode array. In an exemplary embodiment, theinput device 8320 could be a trigger on the tool 8200.

Control unit 8310 can be a signal processor or the like, or a personalcomputer or the like, or a mainframe computer or the like, etc., that isconfigured to receive signals from the test unit 3960 and analyze thosesignals to evaluate the data obtained (it can also be used to controlthe implant / control the application of current). More particularly,the control unit 8310 can be configured with software or the like toanalyze the signals from test unit 3960 in real time and/or in near realtime as the electrode array is being advanced into the cochlea byactuator assembly 7720 (if present, and if not present, while the arrayis being inserted / advanced by hand). The control unit 8310 analyzesthe input from test unit 3960, after partial and/or full implantationand/or after the surgery is completed and/or as the electrode arrayadvanced by the actuator assembly 7720 and/or as the electrode array isadvanced by the surgeon by hand. The controller / control unit can beprogrammed to also control the stimulation/control the providing ofcurrent to the electrodes during the aforementioned events / situations.The controller 8310 can evaluate the input to determine if there existsa phenomenon according to the teachings detailed herein. The controllercan evaluate telemetry, or otherwise receive telemetry, form theimplant, via the device that communicates with the implant. That said,in an alternate embodiment, as depicted in FIG. 7 , or in addition tothis, the controller 8310 can output a signal to an optional monitor9876 or other output device (e.g., buzzer, light, etc.), that canprovide the surgeon or other healthcare professional performing theoperation or evaluating the data postoperatively, etc., indicative ofthe data obtained and/or indicative of a conclusion reached by thecontrol unit 8310. Note also that in an exemplary embodiment, thecontrol unit 8310 can be a dumb unit in the sense that it simply passesalong signals to the implant (e.g., the control unit can instead be aseries of, for example, buttons where a surgeon depression is one buttonto provide stimulation to a given electrode). The control unit 8310 canbe an external component of the cochlear implant.

Still, in some embodiments, the control unit 8310 is configured orotherwise programmed to evaluate input and determine if the inputindicates that the electrode array is positioned in a given manner wereotherwise that the electrode array is positioned in a manner differentthan that which was desired or otherwise determine any of the featuresdetailed herein. In an exemplary embodiment, upon such a determination,control unit 8310 could halt the advancement of the array into thecochlea by stopping the actuator(s) of actuator assembly 7720 and/orcould slow the actuator(s) so as to slow rate of advancement of theelectrode array into the cochlea and/or could reverse the actuator(s) soas to reverse or otherwise retract the electrode array within thecochlea (either partially or fully). Alternatively, in embodiments whereactuator assembly 7720 is not present, control unit 8310 could providean indication to the surgeon or the like (via an integrated component,such as a buzzer or a light on the control unit, or an LDC screen, orvia device 9876) to halt and/or slow the insertion, etc. In at leastsome exemplary embodiments, control unit 8310 can be configured tooverride the input from input unit 8320 input by the surgeon or theuser.

Some exemplary embodiments utilize the receiver/stimulator 8710 as atest unit 3910 that enables the action of obtaining the data and theaction of providing current to the electrode, and/or any one or more ofthe method actions detailed herein. In an exemplary embodiment, thereceiver/stimulator 8710 and/or control unit 3810 and/or actuatorassembly 7720 and/or input device 8320 are variously utilized to executeone or more or all of the method actions detailed herein, alone or incombination with an external component of a cochlear implant, and/orwith the interface 7444, which can be used after the receiver/stimulator8710 is fully implanted in the recipient and the incision to implantsuch has been closed (e.g., days, weeks, months or years after theinitial implantation surgery). The interface 7444 can be used to controlthe receiver/stimulator to execute at least some of the method actionsdetailed herein (while in some other embodiments, thereceiver/stimulator can execute such in an autonomous or semi-autonomousmanner, without being in communication with an external component)and/or can be used to obtain data from the receiver/stimulator afterexecution of such method actions.

Some exemplary utilizations of the embodiments of FIGS. 5-9 will now bedescribed, along with some modifications thereto.

Extensive fibrosis formation post-cochlear implantation can be less thanutilitarian, and, in some instances, deleterious, to hearingpreservation. In some instances, very early tissue responsepost-implantation, 1 day, for example, can be used to predict a tissueresponse. Severe hair cell (HC) loss, ossification and formation of theearly tissue response (leading to fibrosis) may be dictated by theamount of intra-cochlear trauma sustained during the surgical approachand insertion of the electrode array.

In some instances, intra-cochlear blood contamination can trigger anintracochlear inflammation, or otherwise can be an indication thattrauma has occurred, such as, for example, as a result of insertion intothe electrode array. The source of the intra-cochlea blood can be, forexample, from micro-tears on the lateral wall or from the cochleostomyin the bony wall of the cochlea. As HC loss, extensive fibrosis, andossification may be directly related to hearing loss, there can beutilitarian value in finding methods to either remove this contaminatingblood from the cochlea or disrupt the intra-cochlear inflammatorycascade in an effort to minimize possible deleterious effects describedabove. Some embodiments are directed to identifying the presence ofblood, or a blood clot, or the presence of trauma, in the cochlea. Insome embodiments, there are methods and/or devices to remove or at leastminimize the deleterious effects of intra-cochlear blood contaminationduring either cochlear implant surgery or immediately post-operatively.In some embodiments, there are methods and/or devices to detect theblood contamination, and, in some embodiments, to do so at a temporallyutilitarian manner in general, and in some embodiments, to do so in atemporally utilitarian manner that is more utilitarian than when done inanother temporal manner. In some embodiments, there is the use of one ormore biomarkers to detect the onset, location, and/or blood clotformation of an intra-cochlear bleed, which can be caused by cochleararray implantation. Some embodiments also include methods of how thisblood clot may be minimized in volume at the time of surgery and/orpost-implantation.

In view of the above, some embodiments include the utilization of, forexample, one or more of the systems detailed above, to obtain electrodevoltage measurements along the electrode array inserted into the cochleaand/or as the electrode array is inserted into the cochlea. Someembodiments also include the identification of electrode voltages thatindicate the local presence of blood and/or clotting. Some embodimentsalso include an analysis, such as an automatic analysis and/orsemiautomatic analysis, such as by the systems detailed above, of theelectrode voltages to determine the source of the blood flow, thetemporal spread of the blood and/or the evolution of the blood clotfurther, some embodiments include utilizing the aforementioned data tomake a determination that there should be removal and/or remediation ofthe blood clot (or resultant inflammatory processes) by physical orpharmacological methods, and also embodiments herein include doing so.

Bipolar stimulation of a cochlear implant, such as where two electrodesof the electrode array implanted in the cochlea or otherwise in thecochlea at the time that bipolar stimulation is executed arerespectively utilized as the source and a sink, produces a dipole withinthe cochlea. The quantity of current flowing out of a current source isat least effectively equal (including equal) to the current flowing backinto the current source, in some embodiments where the source and sinkare located in a cochlea with perilymph immersing both the source and asink in a contiguous manner. By ensuring or otherwise utilizing currentflow in the path of least impedance, the introduction of blood into ahomogenous medium can cause an increase in the impedance between thesource and the sink. In at least some exemplary embodiments, thecochlear implant electrode array 146 provides stimulation to tissueutilizing a current source and sink established by two electrodes of theelectrode array. In an exemplary embodiment, this current sourceprovides sufficient current into tissue of the recipient to evoke ahearing percept. In some embodiments according to the teachings detailedherein, irrespective of whether or not a hearing percept is executed,although some embodiments apply a current that creates current flowwithin the cochlea where no hearing percept is evoked and/or thethreshold level at a given frequency for that recipient is higher thanthe current utilized, while in other embodiments, a hearing percept isevoked, the current flow generated by the stimulating electrodes willflow according to an impedance within the cochlea.

FIG. 10 shows an exemplary conceptual diagram of current flow between asource and a sink of an electrode array within the cochlea. Thus if therelative voltage is measured between ICE16 (ICE being intra-cochlearelectrode — as distinguished from an electrode that is not in thecochlea, at least not when the measurement is executed) and ICE17, whereelectrodes 15 and 18 (ICE electrodes 15 and 18) are the stimulatingelectrodes (source and sink), in some exemplary scenarios, the voltagedifference would be a certain value with respect to a cochlea in whichno blood is present and another value (a higher value, in at least someinstances), where there is blood in the cochlea. Thus, FIG. 10 depicts a4-point impedance measurement regimes. By using such measurementregimes, differences between the 4-point (bulk) measures due todifferent biological mediums can be detected, and used to utilitarianvalue.

More particularly, FIG. 11 depicts exemplary in-vitro measures of4-point impedance using an electrode array immersed in saline, tissue,blood, and clotted blood. The elevated 4-point measures for blood andclotted blood are distinguishable above that of saline and tissuemeasures. Thus, by evaluating the impedance between the read electrodes,the presence and/or absence of certain phenomenon in the cochlea can beinferred or otherwise deduced.

Embodiments include a multi-contact cochlea electrode array, such asthose detailed above, an implant with extra-cochlear electrodes (oranother component, such as one that works in conjunction with theimplanted portion of the cochlear implant, a receiver stimulator (suchas that of the implanted portion), which can be either fully implantedor powered by an external behind the ear (BTE) processor or otherexternal device. The implanted portion can include a built in-builtamplifier configured to measure electrode voltages concurrent to thedelivery of electrical current to either the same or adjacent electrodecontacts.

In some instances, a method is executed whereby the implanted portion ofthe cochlear implant (e.g., receiver stimulator) or another device, suchas the control unit detailed above, coordinates measurement electrodevoltages in response to electrical stimulation to one or more contactssuch that a measure of bulk impedance between two electrode contacts canbe estimated. This bulk impedance is calculated for a number oflocations along the electrode array in some embodiments. Thesemeasurements may be repeated continuously over time, either during theinsertion of the electrode array or post-insertion when the electrode isstatic in position (either during the surgery or post-operatively).

Methods further include detection and analysis, wherein, in someembodiments, the system or external apparatus (BTE or computer / controlunit, for example) analyzes the measured impedances / measured voltagesalong the array (at one or more or all possible locations) to determinethe location, density and/or temporal nature of the bulk impedancechanges. These changes in bulk impedance are employed to determine orotherwise infer that blood is present around the electrode array.

FIG. 12 depicts graphs of impedance between read electrodes at twodifferent times (Time A and Time B, for charts A and B, respectively).The graphs depict the impedances between two electrodes, where thenumber presents the electrode with the lower number (i.e., 2 representsthe read pair of electrodes 2 and 3, 20 represents the read pair ofelectrodes 20 and 21, etc.). This number is referred to as the baseelectrode (for no other reason than to establish a standard — if thebase electrode was the higher number, the charts would start with 3 andend with 21, but the data would be the same). As can be seen, theimpedance increases, in some instances, significantly, between time Aand time B for the various read pairs, and in some instances, more forsome pairs than others.

With respect to FIG. 12 , the respective two plots of 4-point impedancesacross the entire electrode array are for measurements immediately afterthe electrode insertion in the operating room and then a time periodless than 10 minutes (e.g., less than 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10minutes) after the initial inserting / after the measurements for plotA.

Some embodiments include analysis that can detect the spread of theblood along the array and/or characterize the evolution of the bloodclotting process. In some embodiments, there is an analysis thatincludes blood source localization techniques to identify the anatomicalsource (location) of the bleeding in the cochlea. For measures conductedpost-operatively, the bulk impedance measures are analyzed along withthe ECoG signal to determine the progressive development of a fibroticresponse around the electrode array; the ECoG component can be utilizedto determine if the biomechanics (such as the displacement of thebasilar membrane) of the cochlear are impacted by this fibrotic growth,as seen in FIG. 13 . Specifically, the graph of FIG. 13 depicts the4-point and cochlear microphonic response changes between anintra-operative and three month post-operative measure. As can be seen,FIG. 13 illustrates a significant change in 4-point impedance profilebetween electrodes 6 and 11 of the array only visible three monthspost-op. The increase in 4-point profile indicates the development ofextensive fibrosis proximal to electrodes 6-11.

In view of the above, FIG. 14 presents an exemplary flowchart for anexemplary algorithm for a method, method 1400, which includes methodaction 1410, which includes energizing one or more electrodes of acochlear electrode array to induce a current flow in the cochlea at aplurality of temporal locations. By way of example only and not by wayof limitation, in an exemplary embodiment, this can include energizingelectrode 19 and/or 22 (where 19 and 22 are alternatingly utilized as asource and sink when both are energized). Other electrode(s) can beenergized. In some exemplary embodiments, the electrodes that areenergized of electrodes and are located at about the middle of theelectrode array (e.g., electrodes 9 and 12), because, in an exemplaryembodiment, that represents a middle ground for blood flow in thecochlea from any direction. In some exemplary embodiments, theelectrodes that are energized by the electrodes that are as proximate asutilitarian to the basal turn (keeping in mind that there is utilitywith respect to having the read electrodes to the basal turn — more onthis below). Any energizement regime that can enable the teachingsdetailed herein can be utilized in at least some exemplary embodiments.Note further that method action 1410 can include energizing differentpairs of the electrodes in a temporally spaced apart manner but wherecollectively, the energizement corresponds to a single temporallocation. For example, in embodiments where the basal turn is the focusof interest, various electrode pairs can be energized as differentsections of the electrode array pass by the turn during insertion.Accordingly, in an exemplary embodiment, for the first temporallocation, the temporal location can span a time period where electrodes19 and 22 are energized, then electrodes 18 and 21 are energized, thenelectrode 17 and 20 are energized, and so on, where the last electrodepair that is energized can end the time period of the first temporallocation. Note also that in an exemplary embodiment, the aforementionedenergizement regime need not necessarily occur only during insertion.Such can be executed while the electrode array is stationary, such asimmediately after full insertion thereof.

With respect to the different temporal locations, the first temporallocation can be executed shortly after the electrode array is fullyinserted into the cochlea, and the second temporal location can beexecuted about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15minutes or any value or range of values therebetween in 1 secondincrements, e.g., about 4 minutes and 13 seconds, between 2 minutes and33 seconds to 3 minutes 22 and seconds, etc.). In some embodiments, thefirst temporal location can be during the insertion process and thesecond temporal location can be any of the aforementioned values afterthe first temporal location.

Method 1400 also includes method action 1420, which includes measuringone or more electrical properties at one or more locations in thecochlea resulting from the induced current flow at the plurality ofdifferent temporal locations. In an exemplary embodiment, the locationcan be at the basal turn of the cochlea, and the measured properties canbe properties that are measured as various electrodes become proximateto the basal turn during insertion of the electrode array. In anexemplary embodiment, the measured electrical properties are atdifferent locations along the electrode array after the electrode afterthe electrode array is fully inserted, which could result in dataaccording to plots A and B of FIG. 12 . That said, the data according toplots A and B of FIG. 12 can also be obtained by reading the readelectrodes as those electrodes become proximate to the specific locationin the cochlea. That is, the first temporal location can correspond to aperiod of time that it takes from the first pair of read electrodes tobecome proximate to a given location to the time that it takes from aless pair of read electrodes to become proximate to a given locationduring electrode insertion. With respect to the aforementioned basalturn location, it could be that in some embodiments, the plots of Aand/or B will begin only at electrode 7 or 8 or 9 or 10 or 11 or 12 orso, as the electrodes below those values may not reach the basal turn,ever.

Method 1400 also includes method action 1430, which includes determiningwhether or not trauma has occurred based on a change between themeasured electrical properties from the first temporal location to thesecond temporal location. In an exemplary embodiment, method action 1430can include the action of analyzing the change in the measuredelectrical property to identify indications of blood (and/or clot) inthe cochlea, and upon a determination that an indication of blood in thecochlea is present, determining that trauma has occurred (or, upon adetermination that an indication of blood (and/or clot) in the cochleais not present, determining that trauma has not occurred).

Method action 1430 can be executed by the control unit of FIG. 5 , or bythe external component of the cochlear electrode array, providing thatsuch is programmed to execute such. This can be done automatically ormanually.

A variation of method 1400 can include the action of evaluating a timeperiod between the first temporal location and the second temporallocation, and, based on the evaluation of the time period, determiningthat trauma has occurred. By way of example only and not by way oflimitation, the second temporal location can be any time after the firsttemporal location. Note that the embodiment of method 1400 can be suchthat the second temporal location can occur after a third, a fourth,fifth, a sixth, a seventh, an eighth, a ninth, or more temporallocations. In this regard, the second temporal location can be atemporal location with the measurements indicate a significant event ascompared to other temporal locations. By way of example only and not byway of limitation, the application of electrical current and themeasurements can be executed for, for example, 10 different temporallocations, where the seventh temporal location after the first temporallocation is the first temporal location that indicates a significantchange in the impedance at the location(s) of interest in the cochlea.In this regard, by way of example only and not by way of limitation,with respect to the plots of FIG. 12 , the seventh temporal locationcould be the first temporal location where the measurements results inone or more impedances that are above 800 ohms, as is represented by wayof example only and not by way of limitation, in plot B. Accordingly,the time period between the first temporal location and the seventhtemporal location can be evaluated, and upon a determination that thetime between the two meets a certain criteria (or does not meet acertain criteria), a determination can be made that trauma has occurred(for example, trauma resulting at the time of insertion or otherwiseproximate thereto). By way of example only and not by way of limitation,if the time period between the temporal locations is less than 1, 2, 3,4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,23, 24, 25, 26, 27, 28, 29, or 30 minutes), depending on othercircumstances in some instances, a determination can be made that traumahas occurred, and if the time period between the temporal locations isgreater a value, a determination can be made that trauma has notoccurred. Note also that the latter temporal location can simply be afinal temporal location. There need not be a rise in impedance. The lackof a rise in impedance by the second temporal location can indicate notrauma. That is, based on the evaluation of the time period between thepertinent temporal locations, a determination is made that trauma hasnot occurred.

FIG. 15 presents another exemplary algorithm for an exemplary method,method 1500, which includes method 1510, which includes executing method1400. Method 1500 also includes action 1510, which includes analyzingthe change in the measured electrical property(s) to identify thepresence or absence of indications of blood in the cochlea, and includesmethod action 1520, which includes, upon a determination that anindication that blood in the cochlea is or is not present, determiningthat trauma has nor has not occurred, respectively. It is noted that avariation of the method 1500 includes analyzing the change in themeasured electrical property(s) to identify indications of blood in thecochlea and upon a determination that an indication that blood in thecochlea is present, determining that trauma has occurred, while anothervariation includes analyzing the change in the measured electricalproperty(s) verify that there are no indications of blood in the cochleaand upon a determination that an indication that no blood in the cochleais present, determining that trauma has not occurred.

FIG. 1600 presents an exemplary method, method 1600, according to anexemplary embodiment. Method 1600 includes method action 1610, whichincludes executing method 1400. Method 1600 also includes method action1620, which includes determining that trauma has occurred, and executingmethod action 1630, which includes executing source localizationtechniques to identify an anatomical location of the trauma within thecochlea. In an exemplary embodiment, a spike in the measurementsreadings at certain electrodes can be used to indicate or otherwiselocalize the point where the bleeding occurs or where there is a tear inthe outer wall of the cochlea. (It is noted that in at least someinstances, the 90° curve of the cochlea is a location that tends to be,statistically speaking, more prone to trauma than other locations withinthe cochlea. As will be described in greater detail below, embodimentsinclude focusing on this location, and upon a determination that alocalized increase in impedance is present at that location as opposedelsewhere, a determination can be made there is a high likelihood thattrauma has occurred at the location. The focus on this location can alsobe utilized as a manner to eliminate false positives - if the localizedincreases occur at this location and not elsewhere, it is likely anindication that the data is correct, as opposed to the existence ofincreases in impedance at other locations as opposed to this location -not that that cannot happen, but such would be indicative of potentiallyanother problem other than a tear in the cochlea wall.)

In this regard, in an exemplary embodiment, the impedances between readelectrodes closer to a source of blood flow into the cochlea willincrease, in some embodiments, at temporal locations before impedanceincreases between read electrodes at locations further away to a sourceof blood flow into the cochlea. Accordingly, in an exemplary embodiment,there is a method of evaluating the temporal locations of increases inimpedance measurements at different spatial locations along theelectrode array and comparing the spatial locations and the temporallocations to each other to determine the location of the trauma. Forexample, in an exemplary embodiment where there is an electrode arraythat is fully inserted in the cochlea, where for the purposes ofdiscussion herein, electrode 1 is the most basal electrode and electrode22 is the most apical electrode, and increase at temporal location 10 ofimpedance between read electrodes 10 and 11 that is greater than anyimpedance increase between read electrodes 7 and 8 and/or, for example,at read electrodes 14 and 15, at temporal location 10, where, forexample, subsequently after temporal location 10, at temporal location11 for example, an increase in impedance is seen between the readelectrodes 7 and 8 and 14 and 15 relative to that which existed atlocation 10, a determination can be made that the source of the traumais at a location proximate read electrodes 10 and 11.

Another way of identifying an anatomical location of the trauma withinthe cochlea could be to look at the different impedances between readelectrodes for a single given temporal period. By way of example, plot Bof FIG. 12 indicates that there could be trauma at a location aroundelectrodes 7, 8, 9, 10, 11, and 12 and/or around electrodes 15, 16, 17,and 18, based on the fact that the impedances are higher at thoselocations.

In at least some exemplary embodiments, the underlying physicalphenomenon upon which some of the teachings detailed herein rely,without being bound by theory, is that the trauma can be a tear orlaceration in a wall of the cochlea, and that the blood will first enterthe cochlea at that location, and thus there will be an increase in theimpedance of the fluids inside the cochlea beyond that which would bethe case for normal perilymph, and that this would be localized,initially, at the trauma location, and then, over time (over seconds orminutes), the blood would defuse or otherwise disperse throughout thecochlea in a more uniform manner. By obtaining readings in closetemporal proximity to the beginning of blood flow into the cochlearelative to later temporal periods, the location of the intrusion, andthus the trauma, can be identified.

Note also that in an exemplary embodiment, it is possible that diffusiontechniques are not utilized per se. In this regard, by way of example,putting cold water into a pool where the body of water has a highertemperature than the cold water will result in the temperature near theintroduction of the cold water being lower than it locations elsewherefrom the pool, even though the cold water is constantly being diffusedthroughout the pool. Indeed, plot B of FIG. 12 can represent thisphenomenon, or, in another scenario, the impedances can be elevated atmany if not all locations along the array, but the most pronouncedimpedance increase could be at the location proximate the trauma.

By utilizing any of the various known techniques to correlate locationelectrodes and an electrode array with the local anatomy of the cochlea(e.g., by electrode wetting, by counting the number of electrodes thathave been inserted into the cochlea or the number of electrodes that arenot inserted into the cochlea, and thus determining how far theelectrode array has been inserted into the cochlea, and thus therelative location of various electrodes from the entrance point into thecochlea, by imaging techniques, impedance techniques, etc.), thelocation of the trauma can be identified by identifying the electrodesexperiencing the impedance increase.

It is noted that in at least some exemplary embodiments, techniques areutilized to evaluate whether the increased impedances due to blood flowor due to some other phenomenon, such as, by way of example only and notby way of limitation, those particular electrodes of interest beingcloser to the modiolus wall of the cochlea relative to other electrodes,an open circuit in the implant, etc. Accordingly, in some exemplaryembodiments, the action of determining the presence or absence of traumais combined with other techniques to evaluate the underlying cause ofthe impedance increase to increase the likelihood that the impedanceincrease is a result of trauma and not some other physical phenomenon.

In view of the above, being that in an exemplary embodiment, there is amethod that includes determining that trauma has occurred, analyzing achange in measured electrical properties to identify a location alongthe electrode array of the measured electrical properties, anddetermining a location of the trauma within the cochlea based onlocation along the electrode array.

FIG. 17 presents another exemplary algorithm for an exemplary method,method 1700, which includes method action 1710 and method action 1720,which respectively include executing method 1400 and determining thattrauma has occurred. Method 1700 also includes method action 1730, whichincludes therapeutically treating the cochlea upon a determination thattrauma has occurred.

In an exemplary embodiment, method action 1730 is executed by mitigatingan inflammatory response, where, once blood is detected in the cochlea,a series of actions are undertaken to at least attempt to remove thecontaminant (blood/clot). Alternatively, and/or in addition to this,especially if such is unsuccessful, actions are taken to treat thecochlea locally with a drug agent that is configured to minimize orinterrupt any inflammatory cascade that leads to the eventual fibrosis.By way of example only and not by way of limitation, method action 1730can be achieved by one or more or all of the actions:

-   a. Flushing the cochlea with a saline solution using a fine    catheter, or the electrode array itself (via an electrode lumen with    exiting hole at the apex of the array, or any other device or system    that can have utilitarian value.-   b. Bulk impedances are again measured to determine if the presence    of the blood or blood clot has been removed successfully, and a    comparison between these new readings can be made to other data (for    example, the impedance between electrodes for a saline solution can    be known (either based on analytic or empirical prior evaluations,    and/or based on the fact that as the saline is inserted into the    cochlea, the saline will eventually overwhelm the blood, and thus    the saline will be a driver of impedance values until the blood    begins to take a more dominant role)).-   c. In the event blood or clots remain, either in full or in part    thereof, a pharmacological intervention is undertaken. Here a    measured quantity of drug agent can be released into the cochlea    using methods such as charge activated elution or catheter connected    to a pump, or any other therapeutic treatment, such as a systemic    treatment, can be utilized.

It is noted that the above therapies can have utilitarian value withrespect to preserving residual hearing. In this regard, the bloodintroduction can be something that leads to fibrous tissue growth orother growth of tissue in the cochlea that ultimately reduces the amountof residual hearing the recipient can have or otherwise retain after thecochlear implant electrode array is implanted into the cochlea. In thisregard, recipients of cochlear implants can sometimes have residualhearing at the low and medium frequencies. It is the higher frequenciesthat a recipient can have problems hearing which could result in autilitarian value of a cochlear implant. Accordingly, by identifying thepresence of blood in the cochlea according to the teachings detailedherein and/or variations thereof, and taking actions or otherwise atleast accounting for such, exemplary embodiments include improving thepercentage chance that the recipient will retain at least 30, 40, 50,60, 70, 80, 90 or 100 percent of his or her residual hearing that ispresent one week after the insertion of the electrode array 3 or 4 or 5or 6 or 7 or 8 or 9 or 10 or 11 or 12 months after the insertion of theelectrode array by at least 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80,85, 90, 95 or 100%, relative to that which was the case in the absenceof implementing the methods detailed herein, all other things beingequal.

In view of the above, it is to be understood that in some exemplaryembodiments, the action of measuring an electrical property(s) at alocation in the cochlea resulting from the induced current flow at theplurality of different temporal locations is part of an action ofmeasuring respective electrical properties at a plurality of locationsin the cochlea using four point impedance measurements, the plurality oflocations corresponding to locations of, respectively, at least Xelectrodes of the electrode array, where X can be 1, 2, 3, 4, 5, 6, 7,8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 3, 37, 38, 39, or 40 or more.The method further includes the action of determining whether or nottrauma has occurred based on a change between the measured electricalproperties from the first temporal location to the second temporallocation includes identifying a change in impedance between at leastsome neighboring electrodes of the at least X electrodes. In anexemplary embodiment, the aforementioned method can further includeidentifying a location of the trauma based on a comparison of the changein impedance between groups of the at least some neighboring electrodes.

FIG. 18 presents an exemplary algorithm for another exemplary method,method 1800, which includes method action 1810, which includes causingcurrent to flow from a first electrode of an intra-cochlea electrodearray to a second electrode of the intra-cochlea electrode array at aplurality of temporal locations, and method action 1820, which includesmeasuring at a third electrode and a fourth electrode of theintra-cochlea electrode array, respective voltages induced by theflowing current at the plurality of temporal locations. Collectively,method actions 1810 and 1820 can be executed utilizing, for example, afour point impedance measurement scheme.

Method 1800 also includes method action 1830, which includes the actionof determining that a change between the voltage measurements at thethird electrode and the fourth electrode has occurred between thetemporal locations, and method action 1840, which includes determining atime period between the temporal locations. This is followed by methodaction 1850, which includes determining whether or not a phenomenon hasoccurred within the cochlea based on the determined time period. By wayof example only and not by way of limitation, if the time period iswithin a few seconds, it might be determined that the changes are basedon the normal reaction when an electrode array is being moved into thecochlea. By way of example only and not by way of limitation, if thetime period is within a few minutes, it might be determined that thechanges are based on a true phenomenon that has occurred within thecochlea.

Consistent with the teachings detailed above, in an exemplaryembodiment, the phenomenon is blood entry into the cochlea. In anexemplary embodiment, the phenomenon is trauma to the cochlea due toelectrode array insertion. In an exemplary embodiment, the phenomenon istrauma that results during a period of time starting with the time thatthe first electrode is fully inserted into the cochlea and ending at orafter or before electrode 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32,33, 34, 35, 3, 37, 38, 39, or 40 (if the electrode array has suchnumber, and if not, reduced accordingly). It is noted that theaforementioned temporal locations noted above can be locations within orbound by this aforementioned time. It is also noted that in an exemplaryembodiment, the first and/or the second or any other temporal locationcan be Z long, where Z is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32,33, 34, 35, 3, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50,51, 52, 53, 54, 55, 56, 57, 59, 60 seconds, or minutes or hours or days(or combinations thereof (e.g., 2 days, 8 hours and 10 minutes) afterany of the events herein that would begin a temporal period, or anyvalue or range of values therebetween in 1 second increments). In someembodiments, the determined time period is a period between about (whichincludes exactly) Z and about Z (where the second Z is larger than thefirst Z, such as 1 to about 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, or 6minutes), and the method further includes determining that thephenomenon has occurred based on that time period. It is noted that thebeginnings and/or ends of the time period need not be keyed to adistinctive event or occurrence. These values can be values where, atthe end of a given time period, statistically speaking, if certainthings are present, certain things can be inferred, irrespective of thefact that the certain things could be present prior to the end of thetime period or the beginning of the time period.

In an exemplary embodiment, the change in voltage measurements resultsfrom an increase in impedance between the electrodes and the determinedtime period is a period between about Z and about Z (about 1 to about 2,2.5, 3, 3.5, 4, 4.5, 5, 5.5, or 6 minutes, for example), and the methodfurther includes determining that the phenomenon has occurred based onthat time period.

In an exemplary embodiment, the determined time period can be longerthan Z, and the method further includes determining that the phenomenonhas not occurred based on the determined time period, where Z could beabout 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 11, 12,13, 14, 15, 16, 17, 18, 19, or 20 minutes. In some embodiments, thephenomenon is blood entry into the cochlea.

In an exemplary embodiment, the change between the voltage measurementsat the third electrode and the fourth electrode is a change that isindicative of fibrous tissue growth within the cochlea if the temporalperiod was longer than a value of Z (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15 days, or weeks). The method further includesdetermining that insertion trauma has occurred because the determinedtime period is less than Z (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,13, 14, 15 seconds, or days). That is, by way of example only and not byway of limitation, plot B of FIG. 12 can, for all intents and purposes,look like what would occur as a result of fibrous tissue growth (orwould be difficult if not impossible to distinguish therefrom). Thedifference is that the plot B of FIG. 12 exists at a temporal locationwhere fibrous tissue did not have time to grow. In this regard, byevaluating the time period, one can distinguish between phenomena. Forexample, if the time period is more than 3 or 4 or 5 or 6 or 7 or 8 or 9or 10 or 11 or 12 or 13 or 14 or 15 minutes or more, in at least someexemplary embodiments, the phenomenon is likely something other thanblood in the cochlea or something other than trauma resulting from theinsertion process of the electrode array, etc., and thus the teachingsdetailed herein include method of determining such.

In an exemplary embodiment, method 1800 further includes the action ofdetermining that trauma has occurred, wherein the phenomenon is traumato the cochlea due to electrode array insertion (as opposed to postinsertion trauma that occurs after the electrode array is fullyinserted, or after the skin is closed during surgery, etc.), and themethod further includes determining a location of the trauma within thecochlea based on the location of the third electrode and the forthelectrode relative to other electrodes where a change in voltagemeasurements between such is less than that between the third and thefourth electrodes during the determined time period. In an exemplaryembodiment, the difference in voltage measurements is such that thelower voltage is no more than about 5, 6, 7, 8, 9, 10, 15, 20, 25, 30,40, 50, 60, 70, 80, or 90 percent of the higher voltage, or any value orrange of values therebetween in 1% increments).

FIG. 19 presents an algorithm for an exemplary method, method 1900,which includes method action 1910, which includes the action of applyingat first and second temporal locations respective electrical currents toone or more electrodes located in a cochlea of a recipient. This can bedone by applying electrical currents to only one group of a source andsink at a first temporal location and then applying electrical currentsto that group or another group of a source and a sink without applyingcurrent to any other electrodes. This can be done by applying electricalcurrents to more than only one group of a source and a sink, such as byway of example only and not by way of limitations, 2 groups, 3 groups,4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,23, 24, 25, 26, 27, 28, 29, or 30 or more groups (where the applicationof electrical current is staggered temporally, but all within the firsttemporal location) where every group has a source or sink that isdifferent from that of another group, during a first temporal location,and then repeating that at the second temporal location, or using moreor less groups or doing a variation of those groups or utilizingcompletely different groups. Any regime of applying electrical currentsto electrodes can be used in some emboidments if enabled. Note also thatin an exemplary embodiment, method action 1910 can be executed utilizingone intracochlear electrode and one extra cochlear electrode, or morethan one intracochlear electrode while utilizing the extra cochlearelectrode as part of all the groups, and so on. Method 1900 alsoincludes method action 1920, which includes obtaining first and seconddata indicative of an electrical property at a location within thecochlea (in some embodiments, this is more generically at a locationaway from the electrodes — which could be the 4 point impedance regime),the first and second data corresponding to data obtained, respectively,at the first and second temporal locations. By way of example only andnot by way of limitation, in an exemplary embodiment, the result ofmethod action 1920 can result in the plots A and B of FIG. 12 . Method1900 also includes method action 1930, which includes evaluating whetheror not there is an existence of a temporal change in an electricalproperty within the cochlea at the location based on the obtained data(note that this is no exclusive to only one property / one change - aslong as the evaluation includes an evaluation of a change in oneproperty, such as covered). Method 1900 also includes method action1940, which includes determining whether or not there is blood and/or aclot in the cochlea based on the temporal change in electricalconductivity. Method action 1940 can be executed by evaluating thechange in impedances at the location between the first temporal periodand the second temporal period.

As noted above, method 1900 includes obtaining electrical properties ata location within the cochlea. It is noted that this does not excludeobtaining electrical properties at more than one location within thecochlea. As long as there is one location within the cochlea where theproperties are obtained, and that is consistent (within capabilities ofthe art) between the first and second temporal periods, such asencompassed by this feature. As will be detailed below, in an exemplaryembodiment, a location of interest can be the first basal turn, and inan exemplary embodiment, method 1900 includes analyzing the change in anelectrical property at that location. The method can include evaluatingchanges in properties at other locations as well.

Briefly, as will be explained in greater detail below, in some exemplaryembodiments, method 1900 and/or the other methods detailed herein aredirected towards focusing only a limited number of locations within thecochlea relative to the entire cochlea. Again, in an exemplaryembodiment, the location of the first basal turn can be the focus ofattention. In this regard, in an exemplary embodiment, as the electrodesare moved to the location within the cochlea, the pertinent electrodescan be energized and the pertinent read electrodes can be utilized, suchas the read electrodes at the location / adjacent to the location ofinterest, and a data set can be developed for that location. By way ofexample only and not by way of limitation, in an exemplary embodiment,the first temporal location can be a location where the most apicalelectrode, electrode 22, first reaches the basal turn of the cochlea tothe where the most basal electrode that reaches the basal turn (e.g.,electrode 8 or 9 or 10 or 11 or so) has indeed reached the basal turn(e.g., electrode array is fully inserted). FIG. 20 represents anexemplary plot A resulting from the first temporal location being thelocation where the most apical electrodes, electrodes 18-22, first reachthe basal turn of the cochlea, where subsequent temporal locationscorrespond to the other electrodes first reaching the basal turn. Inthis regard, each data point represents a different temporal location.In an exemplary embodiment, the first temporal location can correspondto the data points associated with electrode 20 and the second temporallocation can correspond to the data point associated with electrode 9.As can be seen, the electrical property does not change in a significantmatter, and thus a determination can be made that there is no blood atthe location or otherwise blood in general in the cochlea. Conversely,FIG. 21 represents another plot based on the same temporal locationsexcept that as the electrode array is being inserted into the cochlea,it is induces a laceration in the wall and blood flows into the cochleaat the first basal turn. Accordingly, as the temporal locationsprogress, and thus the various electrodes come into the locationcorresponding to the basal turn, the impedance increases as timeprogresses until it levels off. In this regard, the comparison wouldreveal that a change of impedance has occurred between the two temporallocations, and thus a determination would be made that there is a bloodand/or, plot in the cochlea in general, and at that particular location.

Note that the scenario of FIG. 21 represents a relatively large cutwhere relatively large amounts of blood into the cochlea in a period oftime (less than or equal to the time that it takes to get the electrodearray fully inserted into the cochlea — note that in this exemplaryembodiment, because the location of interest is the first basal turn,the electrodes basal of the first basal turn are not utilized, althoughin other embodiments, these electrodes can be utilized as well). In anexemplary embodiment where FIG. 21 represents data obtained as the givenelectrodes pass by the given location (i.e., the data of FIG. 21represents a single spatial location over various temporal locations),as the blood begins to flow from the laceration, there will be moreblood at that particular location, hence the increase from electrodes 17to electrodes 9 as those electrodes reach that location. Conversely,FIGS. 20 and 21 can represent a method where the electrical propertiesare obtained at many different locations over to temporal periods. Inthis regard, in an exemplary embodiment, FIG. 20 can correspond to thatwhich results from taking the four point impedance measurements at atemporal location immediately or close thereto after full insertion(e.g., within 1 or 2 or 3 or 4 seconds), and FIG. 21 can correspond tothat which results from taking the four point impedance measurements ata temporal location 2 or 3 or 4 or 5 or more minutes after fullinsertion. Thus, electrical properties for approximately 10 or 11locations in the cochlea are obtained at both of the temporal locations,and the temporal change in the electrical property at those locationscan be seen. Here, some locations do not show a significant change inresistivity / productivity, while others do show such a change. Based onsuch an analysis, one can determine that there is blood and/or a clot inthe cochlea.

In any event, referring back to method 1900, in an exemplary embodiment,the temporal change is a rapid change in impedance within the cochlea.In an exemplary embodiment, by way of limitation, and impedance changewithin the cochlea can correspond to an increase of 50, 75, 100, 125,150, 175, 200, 250, 300, 350, 400, 450, 500, 550, 600, 700, 800, 900 ormore percent over that temporal period, and depending on the increase, adetermination can be made that there is blood and/or a clot in thecochlea (or trauma, etc.). The time between the two temporal locationscan be any of the Z values detailed above depending on the embodiment.

In an exemplary embodiment where the action of determining whether ornot there is blood and/or a clot in the cochlea includes determiningthat there is blood in the cochlea, method 1900 can further includedetermining a location of an origin of the blood in the cochlea. By wayof example only and not by way of limitation, referring to FIG. 21 ,because the impedances highest at about the location of electrode 9 or10, a determination can be made that the origin of the blood in thecochlea is at a location proximate those electrodes. This can be thecase based on a scenario where FIG. 21 represents the impedances takenwith a stationary electrode two or three minutes etc., after fullinsertion, or where FIG. 21 represents impedances taken as theelectrodes pass by the location where the blood is entering into thecochlea.

In an exemplary embodiment, the action of determining whether or notthere is blood and/or a clot in the cochlea includes determining thatthere is blood in the cochlea, and method 1900 further includesdetermining a location of an origin of the blood in the cochlea based ona comparison of the second data to at least third data indicative ofelectrical properties at a spatial location away from the location, thethird data being obtained at effectively the same time as the seconddata, wherein the second data is obtained after the first data. In anexemplary embodiment, such as where FIG. 21 represents data obtained atdifferent temporal locations for each of the data points, a comparisoncan be made between the data obtained at the location at the 16^(th)electrode, which would be the third data, and a comparison can be madeto the data obtained at the 9^(th) or 10^(th) or 11^(th) or 12^(th)electrode etc., and thus a determination can be made the difference inthe impedances indicates that the location of the origin of blood in thecochlea is at a location proximate the 9^(th) or 10^(th) or 11^(th) or12^(th) electrode etc.

In an exemplary embodiment of utilizing impedances obtained at readelectrodes, the location of trauma or otherwise blood entry into thecochlea can be considered to be the section of the cochlea wall that isclosest to the read electrodes that indicate the heightened impedances.

In an exemplary embodiment of method 1900, the action of applying atfirst and second temporal locations respective electrical currents tothe one or more electrodes located in a cochlea of a recipient isexecuted using a cochlear implant electrode array four point impedancetechnique. In an exemplary embodiment, the temporal change is a changein impedance within the cochlea, and method 1900 further includesevaluating the change in the impedance relative to a time period (e.g.,any of the Z values above, as applicable) and the action of determiningwhether or not there is blood and/or a clot in the cochlea includesdifferentiating between blood and the clot based on the evaluated changerelative to the time period. In an exemplary embodiment, a relativelylonger time period will indicate a clot as compared to blood.

In another exemplary embodiment, with respect to method 1900, againwhere the action of applying at first and second temporal locationsrespective electrical currents to the one or more electrodes located ina cochlea of a recipient is executed using a cochlear implant electrodearray four point impedance technique, and where the temporal change is achange in impedance within the cochlea, method 1900 can further includeevaluating the change in the impedance, wherein the action ofdetermining whether or not there is blood and/or a clot in the cochleaincludes differentiating between blood and the clot based on the changein impedance. In an exemplary embodiment, a relatively larger change inimpedance will indicate a clot as compared to blood.

Still further, in an exemplary embodiment of method 1900, the action ofdetermining whether or not there is blood and/or a clot in the cochleaincludes determine that there is blood in the cochlea and the methodfurther includes monitoring spread of the blood in the cochlea based onimpedance measurements between electrodes inside the cochlea. FIGS.22-26 respectively present plots of impedances obtained along theelectrode array after full insertion at different temporal periods afterfull insertion, with time progressing from FIGS. 22 to 26 . As can beseen, the impedances tend to consistently show a highest level at aroundelectrodes 7 to 10, but over time, the impedances at the otherelectrodes increases to about the same as those electrodes, indicatingthe spread of the blood within the cochlea to those other locations,where the origin of the blood is probably around electrodes 7 to 10. Itis noted that these plots show a gradual increase over time. In analternate embodiment, the data near the entry of the blood can show arapid increase at locations proximate the blood entry location, such asthe bottom curve of FIG. 28 , and then subsequent increases at thatlocation are less rapid, while the other locations increase at a morerapid rate as the blood diffuses (the three curves represent dataobtained at increasing temporal locations (with increasing y-axis valueat electrode 2) from that which resulted in the data of FIG. 22 ).Accordingly, an exemplary embodiment can include evaluating the rate ofchange of electrical properties at given locations along the electrodearray to monitor the spread of blood, and can include comparing the rateof changes to that of other locations etc., to deduce phenomenonoccurring in the cochlea.

FIG. 29 presents another algorithm for another exemplary method, method2900, which includes method action 2910, which includes applying at aplurality of temporal locations respective electrical currents torespective one or more electrodes located in a cochlea of a cochlearelectrode array, and method 2920 which includes obtaining a plurality ofrespective measurement readings from electrodes within the cochlealocated along the electrode array for the respective electricalcurrents. In this exemplary embodiment, the method includes moving theelectrode array in the cochlea, and the action of obtaining theplurality of respective measurement readings is executed such that thereadings are focused at a same location within the cochlea relative toother locations within the cochlea. Again, by way of example only andnot by way of limitation, the movement can be the movement of theinsertion of the electrode array into the cochlea, and the focusing canbe the focus on the first basal turn. Thus, according to an exemplaryembodiment, the plurality of temporal locations can be the temporallocations where the read electrodes of the electrode array first becomeproximate to the location of interest. Again, in an exemplaryembodiment, as the electrode array is being inserted in the cochlea,electrodes 22 and 19 can be utilized as the source and sink, andelectrodes 20 and 21 can be the read electrodes at a temporal locationwhere electrodes 20 and 21 are the most proximate to the basal turn, andthen electrodes 21 and 18 can be utilized as a source and sink, andelectrodes 19 and 20 can be utilized as the read electrodes at thetemporal location where electrodes 19 and 20 are the most proximate tothe basal turn, and then electrodes 20 and 17 can be utilized as asource and sink, and electrodes 18 and 19 can be utilized as the readelectrodes at the temporal location where electrodes 18 and 19 by themost proximate to the basal turn, etc. Accordingly, in an exemplaryembodiment of method 2900, thus same location within the cochlea is alocation at or proximate a basal turn of the cochlea, and/or the methodis executed during the electrode array insertion into the cochlea.

In an exemplary embodiment of method 2900, the method is executed duringelectrode array insertion into the cochlea, and during the period whenthe electrode array is being driven into the cochlea, with respect tothe electrodes of the electrode array, at least effectively onlyelectrodes at or proximate the same location are used as measurementelectrodes to obtain the respective measurement readings. By way ofexample only and not by way of limitation, in an exemplary embodiment,such as where the only location of interest is the basal turn of thecochlea, the measurement electrodes utilize are those that are locatedproximate or at the basal turn, and the other electrodes are notutilized, at least not effectively (perhaps some instances all of theelectrodes are utilized, but the bulk of the data collection is based ononly those electrodes that are at or proximate the location). In anexemplary embodiment, more than 20, 25, 30, 35, 40, 45, 50, 55, 60, 65,70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99% of the datacollected comes from electrodes that are at or proximate the locationwith respect to data collected during insertion of the electrode arrayand/or for a temporal. That extends beyond (including or starts after)full insertion of the electrode array. In an exemplary embodiment, thetemporal period can be any of the Z values detailed above from the pointwhere the electrode array first enters the cochlea and/or from the pointwhere the electrode array is fully inserted into the cochlea. It is alsonoted that the aforementioned percentages can be also applicable to theenergized electrodes. That is, the aforementioned percentages cancorrespond to the percentage of current that is applied to theelectrodes at or proximate the location of interest for theaforementioned insertion and/or for the aforementioned time periods. Itis noted that in at least some exemplary embodiments, other locations ofinterest can be included in method 2900. In an exemplary embodiment,effectively only electrodes at or proximate to the same locations orthree of the same locations are used as measurement of electrodes, withthe aforementioned percentages or qualifiers being applicable thereto inat least some exemplary embodiments.

In an exemplary embodiment, again where method 2900 is executed duringelectrode array insertion into the cochlea, and during the period whenthe electrode array is being driven into the cochlea, with respect tothe electrodes of the electrode array, other than for neural responsedetection, at least effectively only electrodes at or proximate the samelocation are used as measurement electrodes to obtain the respectivemeasurement readings. Some additional details of the neural responsedetection will be described below (ECoG, and NRT). It is noted that inat least some exemplary embodiments, the aforementioned percentages andqualifiers applied to this embodiment as well.

In an exemplary embodiment, again where method 2900 is executed duringelectrode array insertion into the cochlea, during the period when theelectrode array is being driven into the cochlea, with respect to theelectrodes of the electrode array, at least effectively only electrodesat or proximate the same location are supplied with electrical current.

In an exemplary embodiment, the electrodes that are used as readelectrodes and/or energized electrodes fall within a distance of no morethan 0.5, 0.75, 1, 1.25, 1.5, 1.75, 2, 2.5, 3, 3.5, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, or 15 millimeters from a line taken normal to atangent at the beginning of the first basal turn at the lateral wall.

Consistent with the embodiments detailed above with respect to limitingthe read electrodes to those at or proximate the given location, in anexemplary embodiment of the method 2900, the electrode array includes atleast X plus 5 electrodes (e.g., 6, 7, 8, 9, 10, 11, 12, etc.), themethod is executed during electrode array insertion into the cochlea andthe action of obtaining a plurality of respective measurement readingsfrom electrodes within the cochlea located along the electrode array forthe respective electrical currents is executed for electrodes thatbecome at or proximate the same location as the electrode array isinserted into the cochlea and not doing so for electrodes that are notproximate to the location. In an exemplary embodiment, during insertionof the electrode array, the pattern of utilization of electrodes as readelectrodes and/or the pattern of applying electrical current toelectrodes is such that the most apical electrodes are first utilizedbefore electrodes basal thereto, and then electrodes basal to the mostapical utilized, and so on, without using again electrodes apical to anelectrode that is used as a read and/or energized electrode again duringinsertion.

In an exemplary embodiment, method 2900 further includes the actions ofobtaining additional measurement readings from electrodes, whetherwithin the cochlea or not, determining location of the electrode arrayin the cochlea based on the additional measurements and focusing thereadings based on the determined location.

Some other embodiments include a method that includes the action ofapplying an electrical current to one or more electrodes of an electrodearray located in a cochlea of a recipient, obtaining data indicative ofimpedances between a plurality of groups of two electrodes correspondingrespectively to different locations along the electrode array,evaluating electrical conductivity between the respective electrodes ofthe respective groups, determining the existence of an impedance changebetween the respective electrodes of the respective groups; anddetermining a location, density and temporal feature of the impedancechange.

Utilizing embodiments based on the timing between changes if any, of theelectrical properties can, in some embodiments, reduce or otherwiseeliminate or otherwise enable the detection of false positives. In thisregard, impedance changes occur for a host of reasons, including, asnoted above, fibrous tissue growth, spatial location relative to thecochlea walls, etc. By evaluating changes in impedance based on temporalaspects, a determination can be made that a given impedance change isindeed indicative of trauma to the cochlea in general, and,specifically, the introduction of blood into the cochlea.

It is briefly noted that the term trauma does not include the foreignbody response that results from a typical insertion of the electrodearray. By way of example only and not by way of limitation,calcification or the growth of fibrous tissue owing to the presence of aforeign body, such as the implant, is not a trauma. Conversely, alaceration inside the cochlea would be trauma.

FIG. 30 presents an exemplary algorithm for another exemplary method,method 3000, which includes method action 3010, which includes theaction of inserting a cochlear implant electrode array into a cochlea(the actual movement of the array), and method action 3020, whichincludes the action of interleaving neural response measurements withimpedance measurements between electrodes of the cochlear implantelectrode array during the insertion. In an exemplary embodiment, theneural response measurements are one or both of NRT (Neural ResponseTelemetry) or ECoG and/or the impedance measurements are four pointimpedance measurements.

In an exemplary embodiment of method 3000, the impedance measurementsbetween electrodes of the cochlear implant electrode array are limitedto those associated with electrodes proximate the basal turn of thecochlea during insertion, or are otherwise limited as detailed above. Inan exemplary embodiment, the impedance measurements between electrodesof the cochlear implant electrode array are limited to those associatedwith electrodes proximate no more than three different locations withinthe cochlea during insertion or are limited as detailed above.

As noted above, the teachings detailed herein can be combined withneural response measurements. In this regard, a recipient’s cochlea 120is a conical spiral structure comprising three parallel fluid-filledcanals or ducts, collectively and generally referred to herein ascanals. For ease of illustration, and all the following referencenumbers refer to those of FIGS. 31, 32, and 33 , and thus cannot beconfused with reference numbers from FIGS. 1A to 30 , FIG. 31illustrates cochlea 120 in an “unrolled” arrangement. The cochlea canalscomprise the tympanic canal 146, also referred to as the scala tympani,the vestibular canal 148, also referred to as the scala vestibuli, andthe median canal 150, also referred to as the scala media. Cochlea 140spirals about a recipient’s modiolus (not shown) several times andterminates at cochlea apex 152. Separating the cochlea canals arevarious membranes and other tissue. In particular, toward a lateral sideof the scala tympani 146, a basilar membrane 154 separates the scalatympani 146 from the scala media 150. Similarly, toward lateral side ofthe scala vestibuli 148, a vestibular membrane 156, also referred to asthe Reissner’s membrane, separates the scala vestibuli 148 from thescala media 150. The scala tympani 146 and the scala vestibuli 148 arefilled with a fluid, referred to herein as perilymph, which hasdifferent properties than that of the fluid which fills the scala media148, referred to as endolymph, and which surrounds the organ of Corti(not shown). Sound entering the auricle of a recipient’s ear causespressure changes in cochlea 120 to travel through the fluid-filledtympanic and vestibular canals 146, 148. The organ of Corti, which issituated on basilar membrane 154 in scala tympani 146, contains rows of16,000-20,000 hair cells (not shown) which protrude from its surface.Above them is the tectorial membrane which moves in response to pressurevariations in the fluid-filled tympanic and vestibular canals 146, 148.Small relative movements of the layers of the tectorial membrane aresufficient to cause the hair cells in the endolymph to move therebycausing the creation of a voltage pulse or action potential whichtravels along the associated nerve fiber to the auditory areas of thebrain for processing. The place along basilar membrane 154 where maximumexcitation of the hair cells occurs determines the perception of pitchand loudness according to the place theory. Due to this anatomicalarrangement, cochlea 120 has characteristically been referred to asbeing “tonotopically mapped.” That is, regions of cochlea 120 towardbasal region 160 are responsive to higher frequency signals, whileregions of cochlea 120 toward apical region 162 are responsive to lowerfrequency signals. For example, the proximal end of the basal region 160is generally responsible to 20 kilohertz (kHz) sounds, while the distalend of the apical region is responsive to sounds at around 200 hertz(Hz). In hearing prosthesis recipients, residual hearing most often ispresent within the lower frequency ranges (i.e., the more apical regionsof the cochlea) and little or no residual hearing is present in thehigher frequency ranges (i.e., the more basal regions of the cochlea).This property of residual hearing is exploited in electro-acoustichearing prostheses where the stimulating assembly is inserted into thebasal region and is used to deliver electrical stimulation signals toevoke perception of higher frequency sounds. Ideally, insertion of thestimulating assembly is terminated before reaching the functioningregions of the cochlea where there is residual hearing so that remaininghair cells are able to naturally perceive lower frequency sounds thatcause movement of the perilymph. This concept is illustrated in FIG. 31where reference 164 illustrates the region of the cochlea 120 to whichelectrical stimulation is delivered to evoke hearing perception, whilereference 166 illustrates the region of the cochlea 120 that utilizesacoustic stimulation to evoke a hearing perception. The tonotopic regionof the cochlea 120 where the sound or stimulation output transitionsfrom the acoustic stimulation to the electric stimulation is called thecross-over frequency region, and is illustrated in FIG. 31 by reference168. Recipients of electro-acoustic hearing prosthesis may havedifferent residual hearing characteristics and, accordingly, differentcross-over frequency regions (i.e., transitions occur at differenttonotopic regions of the cochlea). Additionally, insertion of the distalend of a stimulating assembly into and/or past the cross-over frequencyregion can interfere with, or damage, the recipient’s residual hearing.Therefore, as noted above, an objective of the techniques presentedherein is to provide a surgeon with objective measurements that enableinsertion of a stimulating assembly to be halted at a depth, referred toelsewhere herein as the target stop point, that does not interfere withor damage the recipient’s residual hearing. The target stop point, whichis defined as a specific frequency or a specific frequency range(pre-operatively defined insertion stop frequency), is represented inFIG. 31 by reference 170. Also as noted elsewhere herein, a target stopcondition occurs when the distal end or other portion of a stimulatingassembly is inserted to a location (depth) within the cochlea thatcorresponds to (i.e., at or near) the pre-operatively defined insertionstop frequency (i.e., the specific frequency or a specific frequencyrange of the target stop point). As noted above, the intra-operativesystem 105 may utilize any of a number of different types of inner earpotential measurements to determine when the stimulating assembly 126has encountered an insertion stop or warning condition. FIG. 32 is agraph 169 illustrating how inner ear responses in the form of cochlearmicrophonic amplitudes can be used to determine when a measurementcontact approaches, reaches, and passes a tonotopic region of thecochlea associated with a target stop point. The graph 169 of FIG. 32has a vertical axis that represents the amplitude of a measured cochlearmicrophonic amplitudes and a horizontal axis that represents time. Inthe example of FIG. 32 , the cochlea 120 of the recipient is stimulatedwith an acoustic input having at least one selected frequency that isassociated with (i.e., corresponds to) a specific tonotopic region ofthe cochlea 120. As the stimulating assembly 126 is inserted into thecochlea 120, at least one contact of the stimulating assembly 126 (i.e.,the measurement contact) is used to obtain ECoG measurements, whichinclude the cochlear microphonic amplitude. As shown by reference 171 inFIG. 32 , the amplitude of the cochlear microphonic gradually increasesas the measurement contact approaches the tonotopic region of thecochlea associated with the frequency of the acoustic input. As shown byreference 173, the amplitude of the cochlear microphonic peaks when themeasurement contact is located at the tonotopic region of the cochleaassociated with the frequency of the acoustic input. Finally, as shownby reference 175, the amplitude of the cochlear microphonic graduallydecreases as the measurement contact moves away from the tonotopicregion of the cochlea associated with the frequency of the acousticinput.

As noted above, an objective of the insertion process is to stopinsertion of the stimulating assembly 126 when a portion of thestimulating assembly (e.g., a distal end of the stimulating assemblyand/or one or more stimulating contacts) reaches, but does not pass, atonotopic region corresponding to the pre-operatively defined insertionstop frequency (i.e., the target stop point). Therefore, FIG. 32 ismerely illustrative and does not represent cochlear microphonicamplitudes that would be measured in all embodiments. Instead, when thecochlear microphonic amplitude is measured at the pre-operativelydefined insertion stop frequency, the insertion could stop at points 171or, ideally, 173 of FIG. 32 (i.e., before the measurement contact passesthe target stop point). In addition to a target stop condition,embodiments presented herein are also configured to monitor insertion ofa stimulating assembly for warning conditions or an error stopcondition. An error stop condition occurs when a stimulating assemblyphysically contacts or otherwise interferes with the organ of corti(including the basilar membrane 154) at any point along the stimulatingassembly. Contact or interference may be due to, for example, overinsertion, cochlea morphology, improper surgical trajectory, etc.Further details for detection of target stop conditions, an error stopconditions, and warning conditions are provided below.

FIG. 33 is a flowchart illustrating operations associated with detectionof one or more stop conditions in accordance with embodiments presentedherein. For ease of illustration, the method of FIG. 33 is describedwith reference to an intra-operative system and a hearing prosthesisdescried above. The method 175 of FIG. 3 begins at 176 where one or morepre-operative tests/measurements are performed on the recipient toassess the function of cochlea 120 (i.e., the cochlea in which thestimulating assembly 126 is to be implanted). The one or morepre-operative tests can include an audiogram measurement of therecipient’s cochlea 120 in order to record the recipient’s residualhearing (i.e., to determine the frequency and/frequency range where therecipient’s residual hearing begins). An audiogram measurement refers toa behavioral hearing test, sometimes referred to as audiometry, whichgenerates an audiogram. The behavioral test involves the delivery ofdifferent tones, presented at a specific frequency (pitch) and intensity(loudness), to the recipient’s cochlea and the recording of therecipient’s subjective responses. The resulting audiogram is a graphthat illustrates the audible threshold for standardized frequencies asmeasured by an audiometer. In general, audiograms are set out withfrequency in Hertz (Hz) on the horizontal (X) axis, most commonly on alogarithmic scale, and a linear decibels Hearing Level (dBHL) scale onthe vertical (Y) axis. In certain arrangements, the recipient’sthreshold of hearing is plotted relative to a standardized curve thatrepresents ‘normal’ hearing, in dBHL. The audiogram is used to determinethe frequency and threshold of hearing for the recipient’s cochlea. Inaddition to an audiogram measurement, the pre-operative tests can alsoinclude one or more imaging tests, such as a high resolution computedtomography (CT) scan, X-ray, Magnetic resonance imaging (MRI), etc. ofthe recipient’s cochlea. In certain embodiments, the high resolution CTscan, and possibly the MRI, is employed clinically to determine if thereare anatomical abnormities or bone growth (meningitis) prior to thesurgery. The MRI can also be used to determine the viability of theauditory nerve. Moreover, the size of the cochlea may be assessed(estimated) via high resolution CT scans that measure the anatomicallandmarks, which can be used to assist with the prediction of insertiondepth angle.

The one or more pre-operative tests can also include an initial innerpotential measurement, such as an ECoG measurement, that is performedfrom outside of the cochlea (e.g., the round window). The innerpotential measurements can be taken pre-operatively, using a measurementelectrode that is inserted through the tympanic membrane, orintraoperatively before beginning insertion of the stimulating assembly126 (i.e., before drilling the cochleostomy or making the incision inthe round window). In the case of an ECoG measurement, ECoG responsesare evoked using an acoustic input at a number of different frequenciesand a fixed presentation level (e.g., supra-threshold). As such, apre-operative ECoG measurement provides a baseline recording of the ECoGresponses at each of a number of different frequencies along the lengthof the cochlea 120, along with the relative magnitude informationbetween each frequency to indicate a region where maximum ECoG amplitudecan be expected for each frequency.

At 178, the results of the pre-operative measurements (e.g., audiogram,CT scan, initial inner potential measurement, etc.) are used to set atarget stop point for the stimulating assembly 126. As noted above, atarget stop point is a cochlea frequency or frequency range, sometimesreferred to herein as a pre-operatively defined insertion stopfrequency, to which a distal end 133 of the stimulating assembly 126 isexpected to be inserted so as to be located at or near the tonotopicregion where the recipient’s residual hearing begins. In certainembodiments, the target stop point is set at a conservative frequency orfrequency range that would minimize the probability of causing eitherunrecoverable or permanent damage to the residual hearing. As such, thetarget stop depth is a type of predictive estimate or target that, asdescribed below, is monitored and possibly refined during the insertionprocess.

In certain embodiments, normative statistics generated based on priorimplantations for similar recipients can be used to further refine thetarget stop point (i.e., revise the target stop depth based oninformation determined from other recipients having similarcharacteristics/attributes to the subject recipient). For example, therefinement based on normative statistics can be made by taking intoaccount the recipient’s age (i.e., refine based on implantation resultsfrom similarly aged recipients), the one or more imaging tests (e.g.,based on implantation results for recipient’s having similar X-rays, CTscans, etc.), hearing loss, etiology or other shared characteristics.

In addition to the target stop point, the results of the pre-operativemeasurements can also be used to set a minimum insertion depth. Theminimum insertion depth defines the depth to which the distal end 133 ofthe stimulating assembly 126 is estimated to be implanted in the cochleain order to provide acceptable electrical only hearing performance(e.g., based on existing clinical evidence). This minimum insertiondepth would take into account anatomical differences (e.g., smallercochlea sizes, malformations, etc.) identified by the pre-operativemeasurements. In general, the minimum insertion depth could be specifiedas a frequency, frequency range, or an angle. Defining the minimuminsertion depth as an angle takes into account the variations in thecochlea anatomical size and the electrode type (modiolar or lateralwall), etc.

In general, it has been determined that for electrical-only hearing(i.e., only electrical stimulation) with a full length array, there is aminimum insertion depth where maximum clinical benefit can be obtained.Any insertion depth that is under this is distance, again forelectrical-only hearing, will have a poor clinical outcome. It is alsoexpected that, for some recipients, residual acoustic hearing willeventually reduce, leaving only the electrical hearing abilities. Forrecipient’s likely willing to undergo revision surgery (e.g., children),the minimum insertion depth may be an insertion depth where it isensured that the acoustic hearing is fully unperturbed by theintroduction of the stimulating assembly. For recipient’s unlikely toundergo an additional surgery (e.g., older recipients), the minimuminsertion depth may be a depth where it is determined that, when theresidual acoustic hearing deteriorates, the implanted stimulatingassembly will still provide acceptable electrical-only performance.

After setting the target stop point and the minimum insertion depth, thesurgeon begins implantation of the stimulating assembly (e.g. opens thecochleostomy or incises the round window and inserts the distal end intothe cochlea). At 180, the insertion of the stimulating assembly 126 ismonitored using objective inner ear potentials measured, in real-time,via one or more stimulating contacts 138. For example, in certainembodiments one or more acoustic tones (e.g., pure tone(s)) at aselected frequency or frequencies are delivered to the recipient’s outerear using, for example, the receiver 142. The acoustic signals deliveredby the receiver 142 cause displacement waveforms that travel along thebasilar membrane. These waves grow in amplitude and reach a maximum atthe characteristics frequency (CF) as a function of frequency along thecochlea. These vibrations along the cochlea give rise to an inner earpotential. Therefore, in response to the delivered acoustic signals, oneor more of the stimulating contacts 128 and the integrated amplifier(s)143 of the cochlear implant capture one or more windows of the evokedactivity (i.e., perform ECoG measurements) to generate inner earresponse measurements (e.g., ECoG response measurements) that areprovided to the intra-operative system 105. In other words, theintra-operative system 105 monitors the inner ear response at one ormore of the stimulating contacts 138.

In certain examples, the acoustic signals delivered by the receiver 142are selected based on the results of the one or more pre-operativetests. For example, the acoustic signals can have a frequency that isthe same as, or close to, the frequency of the target stop point (e.g.,at a frequency where the augmented hearing (electrical and acoustic)offers the maximal clinical benefit, around a predetermined cutofffrequency where acoustic hearing starts, etc.,) determined from thepre-operative audiogram. At 182, an insertion stop condition is detectedand, in response to the detection, a feedback mechanism isinitiated/triggered. As noted above, an insertion stop condition caninclude a target stop condition, meaning that the intra-operative system105 has determined that a selection portion of the stimulating assembly126 (e.g., distal end 133, one or more contacts 138, etc.) has reachedthe tonotopic region corresponding to the frequency defining the targetstop point. If the target stop condition is detected, insertion of thestimulating assembly 126 should be terminated to prevent damage to therecipient’s residual hearing.

Also as noted above, an insertion stop condition can also be an errorstop condition, meaning that the stimulating assembly 126 has interferedwith (e.g., come into physical contact with) an intra-cochlea structure,such as the basilar membrane. For example, it is possible that thestimulating assembly can move outwards towards the scala wall, at pointsother than the apical region of the stimulating assemble (e.g., amodiolar hugging array, which is flexible, can reach a point in theinsertion when it meets physical resistance and bows outwards to thescala wall, riding up the wall to eventually make physical contact withthe basilar membrane). If an error stop condition is detected,corrective action should be initiated.

In accordance with the embodiments presented herein, the insertion stopor warning conditions can be detected in a number of different manners.More specifically, referring first to the detection of a target stopcondition, one or more objective inner ear potential measurements, suchas ECoG measurements, are continually performed in real-time while thestimulating assembly 126 is inserted into the cochlea 120 (i.e., as thestimulating assembly 126 is moved in an apical direction). Theintra-operative system 105 analyzes the measured real-time inner earpotentials relative to one another to determine if a change in themeasured response occurs. The change may be, for example, an expectedchange in the magnitude/amplitude, phase, shape of the response/waveform(morphology), frequency, or other aspects of the responses. For example,in one embodiment, an expected change indicative of a target stopcondition comprises the detection of a peak or near peak inacoustically-evoked inner ear potentials (e.g., CM components of ECoGresponses).

Again, in accordance with embodiments presented herein, the real-timeinner ear potential measurements can be made in a number of differentmanners at one or more locations (e.g., simultaneously, sequentially,etc.) within the cochlea. In certain embodiments, inner ear potentialmeasurements can be used to monitor or track the progression of thestimulating assembly 126 within the cochlea 120 using one or morecomplex acoustic inputs (sound signals) comprising multiple frequencies.In other words, inner ear potential measurements can be performed basedon several different acoustic frequencies and/or at different contactsof the stimulating assembly (i.e., multi-frequency acoustic inputsand/or multi-electrode/contact recording). The complex acoustic inputsmay comprise, for example, a frequency sweep signal, a series of soundchirps, etc. More specifically, the intra-operative system 105 can beconfigured to perform inner ear potential measurements at any of anumber of contacts (in response to the same or different acousticinput), and then perform a comparison relative to another and/or againstprevious time points (e.g., pattern matching, correlation, etc.). Signalfeatures that can be compared at, for example, different time points(cross-time point comparison) include phase, amplitude, morphology, etc.Based on the comparisons, the intra-operative system 105 coulddetermine, for example, current insertion depth, location relative tothe predicted depth, basilar membrane contact, stimulating assemblydeformation (e.g., bowing), tonotopic mapping in the cochlea, changes tothe acoustic resonant properties of the cochlea, etc.

In summary, the inner ear potential measurements in accordance withembodiments presented herein may make use of multi-electrode recording,complex acoustic inputs, cross-time comparisons, and/or cross-electrodecomparisons. These variations could, for example, enable the system togauge the current tonotopic position of the measurement contact(s)(e.g., apical electrode) and/or to set a baseline that makes early stagedetection of a “shift” in the cochlea microphonic (such as a change inresonant frequency) easier to detect.

In certain embodiments, one or more complex acoustic inputs (e.g., afrequency sweep signal or a series of sound chirps) are used tocorrelate the position of one or more contacts with a frequency responseas the array advances within the cochlea. That is, the one or morecomplex acoustic inputs enable the intra-operative system 105 to detectthe current tonotopic position of one or more contacts and, accordingly,the position of the stimulating assembly 126. In one such example, oneor more complex acoustic inputs are delivered to the cochlea 120 toevoke responses along the cochlea at tonotopic locations preceding thetarget frequency (i.e., frequencies that are higher than the target stoppoint). Using these responses, the intra-operative system 105 can thendetermine when the measurement contacts (e.g., the apical contact)approaches, reaches, and passes the tonotopic region of the cochleaassociated with each of the frequencies. As noted above, FIG. 32illustrates an example of a cochlear microphonic amplitude measured as ameasurement contact approaches, reaches, and passes the tonotopic regionof the cochlea 120 that corresponds to the frequency of an acousticinput.

In an exemplary embodiment, method 3000 includes the action ofinterleaving any one or more of the actions just detailed above, such asthose detailed with respect to FIGS. 31, 32, and/or 33 , with any one ormore of the impedance measurement techniques detailed herein. As notedabove, some embodiments include interleaving neural responsemeasurements with the aforementioned impedance measurements, and suchcan utilize any of the neural response actions just detailed. In anexemplary embodiment, the impedance measurements are taken in analternating manner with the neural response measurements. In anexemplary embodiment, an exemplary method can include first takingneural response measurements, then taking impedance measurements, thentaking neural response measurements, then taking impedance measurements,then taking neural response measurements, then taking impedancemeasurements, and so on, where this cycle (neural response measurementfollowed by impedance measurements or vice versa) is executed at theleast every second or every 2 seconds or 3 seconds or 4 or 5 or 6 or 7or 8 or 9 or 10 seconds during the insertion of the electrode array, orevery time a new electrode is inserted into the cochlea, or based onsome other indicator, etc. It is also noted that in some exemplaryembodiments, the cycle can vary such that there can be one or two orthree or more impedance actions in between every neural responsemeasurement action or vice versa.

Thus, method 3000 can include the action of, during insertion of astimulating assembly into a cochlea of a recipient, monitoring, at anintra-operative system, acoustically-evoked inner ear potentials (and/orneural response based on stimulation of the nerves with the cochlearimplant electrode array — NRT) obtained from the cochlea of therecipient while also monitoring, at the intra-operative system,impedance measurements obtained from within the cochlea. In an exemplaryembodiment, to reduce the time utilized by the impedance measurements(ECoG and NRT can take longer to achieve utilitarian information andthen that required to obtain utilitarian information from impedancemeasurements), the impedance measurements can be focused at areas ofimportance, such as the basal turn, in accordance with the teachingsdetailed above, while other locations are ignored or otherwise relegatedto secondary status (e.g., the amount of time that impedancemeasurements are taken at some locations is much lower than the amountof time that impedance measurements are taken at other locations).

In an exemplary embodiment, method 300 further includes the action of,at the intra-operative system, detecting, based on theacoustically-evoked inner ear potentials (and/or NRT), an insertion stopcondition, and responsive to detection of an insertion stop condition,initiating, at the intra-operative system, a feedback mechanism to stopinsertion of the stimulating assembly into the cochlea, and/or,detecting based on the impedance measurements, an insertion stopcondition, and responsive to detection of an insertion stop condition,initiating, at the intra-operative system, a feedback mechanism to stopinsertion of the stimulating assembly into the cochlea.

An exemplary embodiment of this method can include initiating a feedbackmechanism to stop insertion of the stimulating assembly comprises atleast one of: stopping automated insertion of the stimulating assembly,or generating a stop notification for a surgeon to stop insertion of thestimulating assembly, and/or at the intra-operative system, detecting,based on the acoustically-evoked inner ear potentials, an insertionwarning condition and responsive to detection of an insertion warningcondition, initiating a feedback mechanism to slow insertion of thestimulating assembly into the cochlea. Further, an exemplary method caninclude detecting an insertion stop condition by detecting an error stopcondition comprising a change in the acoustically-evoked inner earpotentials indicative of a mechanical impedance change of the basilarmembrane, and wherein the method further comprises initiating a feedbackmechanism indicating that the stimulating assembly has interfered with abasilar membrane of the cochlea. In an exemplary embodiment, the actionof detecting an insertion stop condition comprises detecting a targetstop condition comprising a relative change in the acoustically-evokedinner ear potentials, indicating that one or more stimulating contactsof the stimulating assembly are located at a tonotopic positioncorresponding to a pre-operatively defined insertion stop frequency, andwherein the method further comprises initiating a feedback mechanismindicating that the stimulating assembly has been inserted to a targetinsertion depth. In an exemplary embodiment, the action of detecting atarget stop condition comprises detecting a peak or near peak in anattribute of the acoustically-evoked inner ear potentials associatedwith the insertion stop frequency.

It is noted that in an exemplary embodiment includes a method ofinserting an electrode array into a cochlea and while the electrodearray is being pushed into the cochlea, a tone or sound or otherwiseacoustic stimulation is applied as part of an ECoG method. This soundcan be continuous or semicontinuous during the insertion process. In anexemplary embodiment, the sound is used to stimulate the tissue andevoke the neural response for the amount of time that is at least 10,15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or100% of the time between the first electrode entering the cochlea untilthe last electrode enters the cochlea and/or the electrode array isfully inserted into the cochlea / until the electrode array reaches alocation that corresponds to the furthest the electrode array is everinserted into the cochlea. In an exemplary embodiment, the impedancemeasurements are taken while the aforementioned sound is stimulating thetissue / evoking the neural responses. In an exemplary embodiment, theECoG measurements are taken while the aforementioned sound thestimulating the tissue/evoking mineral responses. Again, in an exemplaryembodiment, the method of inserting the electrode array into the cochleais executed while the sound is being played and otherwise evoking theneural responses, and during this time, the electrodes are being used totake the impedance measurements and/or the ECoG measurements.Accordingly, in an exemplary embodiment, there is a method that includesexecuting a portion of an ECoG method in general, and specifically,executing the acoustic stimulus to evoke the neural response, and whilethis neural response is occurring, taking the impedance measurements toexecute one or more or all of the actions associated with the impedancemeasurements detailed herein.

In view of the above, an exemplary embodiment includes a method where,while the sound is applied, the ECOG measurements are interleaved withthe impedance measurements.

Note also that while in some embodiments, the sound is constantlyplayed, in other embodiments, the sound is played for only thoseportions of the insertion where it is more likely than not that the ECOGmeasurements will be utilitarian. For example, the sound could be begunto be played at a location somewhere before the do not exceed locationsuch that there is very little likelihood that the electrode array willreach that location while the sound is not played. This will results, insome embodiments, to the sound being played during times where the ECOGmeasurements are not needed or otherwise less valuable than at otherareas.

In an exemplary embodiment, the methods herein and the systems hereinare such that the electrodes that are energized for the impedancemeasurements are not used as measurement electrodes for the ECOGmeasurements. In an exemplary embodiment, an exemplary method includesexecuting both ECOG measurements and impedance measurements duringinsertion, where the most distal electrode is not used as a source orsink. In an exemplary embodiment, an exemplary method includes executingboth ECOG measurements and impedance measurements during insertion ofthe electrode array, where the second and or third and/or fourth mostdistal electrodes are never utilized as a source and/or a sinkelectrode. In an exemplary embodiment of this embodiment, the mostdistal electrode is used as a source and/or a sink.

An exemplary embodiment includes utilizing electrodes that are utilizedas a source and/or a sink during impedance measurements as measurementelectrodes for the ECOG measurements, except that the time periodbetween the utilization of such as a source and/or a sink and theutilization as a measurement electrode is such that any polarization orotherwise charge buildup is reduced relative to that which would be thecase if the electrodes were used as a source and a sink and ameasurement electrode in a shorter time period.

Thus, in view of the above, there is a method that includes executingneural response measurements N times, where N equals 1, 2, 3, 4, 5, 6,7, 8, 9, or 10 or more, followed by the execution of impedancemeasurements P times, where P equals 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 ormore, followed by the execution of neural response measurements Q times,where Q equals 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 followed by theexecution of impedance measurements T times, where T equals 1, 2, 3, 4,5, 6, 7, 8, 9 or 10 followed by the execution of neural responsemeasurements U times, where U equals 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10followed by the execution of impedance measurements V times, where Vequals 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 followed by the execution ofneural response measurements R times, where R equals 1, 2, 3, 4, 5, 6,7, 8, 9, or 10 followed by the execution of impedance measurements Stimes, where S equals 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 followed by theexecution of neural response measurements W times, where W equals 1, 2,3, 4, 5, 6, 7, 8, 9, or 10 followed by the execution of impedancemeasurements F times, where F equals 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10,wherein the first measurement of the action of interleaving can be animpedance measurement or a neural response measurement.

Further, in view of the above, there is a method that includes executingneural response measurements any number of times equal to an integerbetween 1 and 100 followed by executing impedance measurements anynumber of times equal to an integer between 1 and 100, and repeatingthis process in full or in part an integer number of times equal to 1and 100.

In an exemplary embodiment, there is a method detailed above, whereinthe action of interleaving comprises executing one or more completeneural response measurements followed by the execution of focusedimpedance measurements followed by the execution of one or more completeneural response measurements followed by the execution of focusedimpedance measurements followed by the execution of one or more completeneural response measurements followed by the execution of focusedimpedance measurements followed by the execution of one or more completeneural response measurements followed by the execution of focusedimpedance measurements. In an exemplary embodiment, there is a methoddetailed above, wherein the action of interleaving comprises executingone or more complete neural response measurements followed by theexecution of focused impedance measurements, wherein this is repeated,in whole or in part, any number of times equal to an integer between 1and 100.

Any method action detailed herein corresponds to a disclosure of adevice and/or a system for executing that method action. Any disclosureof any method of making an apparatus detailed herein corresponds to aresulting apparatus made by that method. Any functionality of anyapparatus detailed herein corresponds to a method having a method actionassociated with that functionality. Any disclosure of any apparatusand/or system detailed herein corresponds to a method of utilizing thatapparatus and/or system. Any feature of any embodiment detailed hereincan be combined with any other feature of any other embodiment detailedherein providing that the art enables such, unless such is otherwisenoted.

Any disclosure herein of a method of making a device herein correspondsto a disclosure of the resulting device. Any disclosure herein of adevice corresponds to a disclosure of making such a device.

Any one or more elements or features disclosed herein can bespecifically excluded from use with one or more or all of the otherfeatures disclosed herein.

While various embodiments of the present invention have been describedabove, it should be understood that they have been presented by way ofexample only, and not limitation. It will be apparent to persons skilledin the relevant art that various changes in form and detail can be madetherein without departing from the scope of the invention.

What is claimed is: 1-36. (canceled)
 37. A method, comprising: applyingan electrical current to one or more electrodes of an electrode arraylocated in a cochlea of a recipient; obtaining data indicative ofrespective impedances between electrodes of a plurality of groupselectrodes, respective groups of the plurality of groups including atleast two electrodes corresponding respectively to different locationsalong the electrode array; determining an existence of a differencebetween respective impedances between electrodes of a first group ofelectrodes of the plurality of groups of electrodes and betweenelectrodes of a second group of electrodes of the plurality of groups ofelectrodes; and at least one of: determining a location of thedifference of at least one of the groups of electrodes representing theexisting difference; or applying a treatment based on the determinedexistence.
 38. The method of claim 37, further comprising: determiningthe location of the difference of at least one of the groups ofelectrodes representing the existing difference.
 39. The method of claim37, further comprising: applying a treatment based on the determinedexistence.
 40. The method of claim 39, wherein: the treatment isflushing the cochlea.
 41. The method of claim 39, wherein: the treatmentis flushing the cochlea with a saline solution.
 42. The method of claim39, wherein: the treatment is applying a drug agent to the cochlea. 43.The method of claim 37, further comprising: determining a location,density and temporal feature of the impedance change.
 44. The method ofclaim 37, further comprising: determining that trauma has occurred; anddetermining the location of the trauma within the cochlea based onlocation along the electrode array of the difference of at least one ofthe groups of electrodes representing the existing difference.
 45. Amethod, comprising: energizing one or more electrodes of a cochlearelectrode array to induce a current flow in the cochlea at a pluralityof locations; measuring one or more electrical properties at at leasttwo different locations resulting from the induced current flow at theplurality of different locations; and determining whether or not traumahas occurred based on a difference between the measured electricalproperties at the respective different locations.
 46. The method ofclaim 45, wherein: the at least two different locations are spatiallocations.
 47. The method of claim 46, wherein: the at least twodifferent locations are at different spatial locations along theelectrode array.
 48. The method of claim 47, wherein: the at least twodifferent spatial locations are at a same location within the cochlea.49. The method of claim 47, wherein: the measured one or more electricalproperties at a first location of the two different locations issignificantly different from that at a second location of the twodifferent locations; and the determination of whether or not the traumahas occurred includes determining that trauma has occurred based on thesignificant difference.
 50. The method of claim 45, wherein: a diffusiontechnique is used to determine whether or not trauma has occurred. 51.The method of claim 45, wherein: a diffusion technique is not used todetermine whether or not trauma has occurred.
 52. The method of claim45, wherein: the different locations are spatial locations; and thedifferent measurements are taken in a single given temporal period. 53.The method of claim 47, wherein: there are at least ten differentspatial locations of the at least two different spatial locations; theone or more measured electrical properties includes impedance; there areat at least four different spatial locations of the at least tendifferent locations that have impedances that are higher than at otherspatial locations of the at least ten different spatial locations; andthe determination of whether or not the trauma has occurred includesdetermining that trauma has occurred based on the higher impedances. 54.The method of claim 45, further comprising: determining that trauma hasoccurred; and therapeutically treating the cochlea upon thedetermination that trauma has occurred.
 55. The method of claim 54,wherein: the action of therapeutically treating the cochlea includes atleast one of flushing the cochlea or applying a medicament to thecochlea.
 56. The method of claim 45, wherein: the trauma is a tear in awall of the cochlea.
 57. The method of claim 45, wherein: the twodifferent locations are spatial locations; and the method furthercomprises: determining that trauma has occurred; analyzing the change inthe measured electrical property(s) to identify a location along theelectrode array of the measured electrical property(s); and determiningthe location of the trauma within the cochlea based on location alongthe electrode array.
 58. The method of claim 45, wherein: the twodifferent locations are spatial locations; the action of measuring anelectrical property(s) at a location in the cochlea resulting from theinduced current flow at the plurality of different temporal locations ispart of an action of measuring respective electrical properties at aplurality of locations in the cochlea using four point impedancemeasurements, the plurality of locations corresponding to locations of,respectively, at least 7 electrodes of the electrode array; and theaction of determining whether or not trauma has occurred based on achange between the measured electrical properties from the firsttemporal location to the second temporal location includes identifying achange in impedance between at least some neighboring electrodes of theat least 7 electrodes.
 59. The method of claim 58, further comprising:determining that trauma has occurred; and identifying a location of thetrauma based on a comparison of the change in impedance between groupsof the at least some neighboring electrodes.
 60. The method of claim 45,wherein: the at least two different locations are different temporallocations; a change between the one or more electrical properties hasoccurred between the different temporal locations; the change is achange that is indicative of fibrous tissue growth within the cochlea ifthe temporal period was longer than a day; and the method includesdetermining that insertion trauma has occurred because the determinedtime period is less than a day.
 61. The method of claim 45, wherein: Theaction of determining whether or not trauma has occurred includesdetermining that there is blood in the cochlea; and the method furtherincludes monitoring spread of the blood in the cochlea based onimpedance measurements between electrodes inside the cochlea, theimpedance measurements corresponding to the measured one or moreelectrical properties.
 62. The method of claim 45, wherein: air bubblesare present in the cochlea at the time that the one or more electricalproperties are measured; the electrical properties are voltages; theaction of determining whether or not trauma has occurred includesdetermining that trauma has not occurred; and trauma has not occurred.